JP2004069995A - Flash light controller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform photography other than SE lock and operation that a time interval between preliminary light emission and normal light emission is made inconspicuous by a photographer's desire or the like while providing an SE lock function, and to obtain an accurate preliminary photometric value while minimizing energy consumed for the preliminary light emission. <P>SOLUTION: The flash light controller is constituted to perform the photometry of flash light in the preliminary light emission by a sensor selected from a photometric element 9 and a light control element 15. It is selected in accordance with an attached SB main body 50 or selected by user's setting. As for the preliminary light emission, the preliminary light emission with small emitted light quantity is performed for the first time, and whether or not the second preliminary light emission is performed is decided according to the result of the first light emission, and further the emitted light quantity of the second preliminary light emission is varied according to the photometric result of the first preliminary light emission. <P>COPYRIGHT: (C)2004,JPO

Description

【００６０】
表１は、図８〜１２に示した調光制御及び予備発光方式の関係をまとめて示した一覧表である。
図８〜１１により説明した調光制御は、いずれも閃光の測光を調光素子１５により行っており、予備発光の方式（旧フォーマット，新フォーマット）及び調光方式（リアルタイムＴＴＬ，Ｄ−ＴＴＬ）の組み合わせの違いである。一方、図１２に示した制御は、測光素子９を用いて閃光の測光を行っている。測光素子９を用いて閃光の測光を行う場合には、ミラーアップすると、測光不能となるので、リアルタイムＴＴＬ調光は行うことができない。
【００６１】
予備発光の方式については、測光素子を用いた場合でも、旧フォーマットの予備発光を行わせることは、原理的には可能である。しかし、旧フォーマットによる予備発光では、閃光の測光を行っている時間に対して発光している量が少ない。したがって、周囲光が明るいと、光っていない時間に周囲光が入ってきてしまう。一般に測光素子は、調光素子に比べて飽和しやすく、よって、周囲光が明るいと、測光素子９が直ぐに飽和してしまう。一方、新フォーマットの予備発光によれば、閃光が発光している時間だけ測光することができ、測光素子９による予備発光には、新フォーマットが適している。また、先にも述べたように、チョップ発光を繰り返す旧フォーマットの予備発光方式は、エネルギの効率があまり良くない。
そこで、本実施形態では、測光素子９を用いる場合には、新フォーマットの予備発光のみ行うこととしている。
【００６２】
図１３は、カメラマイコン３１のプログラムを示したフローチャートである。カメラのレリーズスイッチ３７が半押しされることによってカメラの電源が入り、本プログラムが実行される。以下に、ステップ（以下、Ｓとする）毎に説明する。
Ｓ１０１では、ＳＥロックの状態を識別するフラグＳＥＬを０にクリアする（非ＳＥロック状態とする）。
Ｓ１０２では、撮影前サブルーチン処理（図１４において説明）を行う。
【００６３】
Ｓ１０３では、不図示のＳＥロックスイッチが押されているか否かを判定する。ＳＥロックスイッチが押されている場合には、Ｓ１０４に進み、ＳＥロックスイッチが押されていない場合には、Ｓ１０５に進む。
Ｓ１０４では、ＳＥロックスイッチが押されていた場合のサブルーチン処理（予備発光１：図１５において説明）を行う。
Ｓ１０５では、レリーズスイッチ３７が全押しされたか否かを判定する。レリーズスイッチ３７が全押しされた場合には、Ｓ１０６に進み、レリーズスイッチ３７が全押しされていない場合には、Ｓ１２０に進む。
【００６４】
Ｓ１０６では、ミラーアップ前のサブルーチン処理（予備発光２：図１６において説明）を行う。
Ｓ１０７では、ミラーアップ、絞り込みを行う。
Ｓ１０８では、ミラーアップ後の予備発光サブルーチン（予備発光３：図１７において説明）処理を行う。
尚、上述の予備発光１〜３及び、後述の図１７における予備発光４は、これらの内いずれかひとつのみが実行されるようになっている（各サブルーチン内において判断される）。
【００６５】
Ｓ１０９では、リアルタイムＴＴＬ調光のアルゴリズム演算（エリア選択、補正量算出）を行う。なお、この演算の内容については、後述する。
Ｓ１１０では、カスタム設定部３８の設定の一つであるカスタム設定に応じて、ストップ信号によるリアルタイム調光制御が選択されているか否かを判定する。リアルタイム調光制御が選択されている場合には、Ｓ１１１に進み、リアルタイム調光制御が選択されていない場合には、Ｓ１１２に進む。
Ｓ１１１では、リアルタイム調光制御を行うために、調光素子１５のゲイン設定を行う。このリアルタイム調光制御は、図８又は図１０のタイムチャートに対応している。ゲインの算出方法については、後述する。
Ｓ１１２では、Ｄ−ＴＴＬ制御の場合の本発光量演算を行う。このＤ−ＴＴＬ制御は、図９、図１１又は図１２のタイムチャートに対応している。Ｄ−ＴＴＬ制御の内容については、後述する。
【００６６】
Ｓ１１３では、カメラからＳＢへ本発光量データ（Ｋｇｎ　、後述）の通信を行う。（図９，１１，１２を参照）
Ｓ１１４では、シャッターを開く（撮影露光開始）。
Ｓ１１５では、リアルタイム調光制御であるか否かの判断を行い、リアルタイム調光制御の場合、Ｓ１１６に進み、調光素子１５の積分を開始する。リアルタイム調光制御でない場合、Ｓ１１７に進む。
Ｓ１１７では、本発光制御を行う。なお、本発光制御は、場合により、リアルタイム調光かＤ−ＴＴＬ調光かのいずれかを行う。
Ｓ１１８では、所定時間でシャッターを閉じ（撮影露光終了）、ミラー、絞りを復帰させる。
Ｓ１１９では、ＳＥロックフラグ（ＳＥＬ）を０にクリアする。
Ｓ１２０では、半押しタイマーが起動後所定時間経過したかどうかを判別し、所定時間内であればステップＳ１０２へ戻って処理を繰り返し、タイマー切れであれば処理を終了する。
【００６７】
図１４は、撮影前処理の制御内容を示したサブルーチンフローチャートである。
図１４に示す撮影前処理は、図１３に示すＳ１０２が実行されると本サブルーチンが呼び出されて実行される。以下、ステップ毎に説明する。
Ｓ２０１では、カメラの諸設定（感度、測光モード、露出モードなど）を読み出す。
Ｓ２０２では、レンズ通信により、撮影レンズの焦点距離、開放Ｆ値、射出瞳距離、距離データなどを読み出す。
【００６８】
Ｓ２０３では、ＳＢ通信により、ＳＢが新フォーマットへ対応しているか否か、モニター発光（小、大）の発光時間、チョップ発光１発当たりの光量、最大本発光量、ＳＢの状態（バウンス状態か否か）等を読み出す。
Ｓ２０４では、定常光測光を行い、Ｂ（１，１）〜Ｂ（５，５）、Ｂ１〜Ｂ５の測光値等を算出する。
Ｓ２０５では、測光値を基に公知の手法により適正露出値を算出し、露出モードに応じて絞り値、シャッター値を算出する。
【００６９】
Ｓ２０６では、焦点検出を行う。
Ｓ２０７では、焦点検出の状態に応じてデフォーカス量が０になるまでレンズを駆動しピントを合わせる。
Ｓ２０８では、合焦位置での撮影レンズのピント距離を被写体距離と見なし、その値をレンズマイコン４１から読み出す。
【００７０】
図１５は、予備発光１の制御内容を示したサブルーチンフローチャートである。
図１５に示す予備発光１は、図１３に示すＳ１０４が実行されると本サブルーチンが呼び出されて実行される。図１３でもわかるように、本フローチャートは、ＳＥロック実行時に適用されるものであり、図１２のタイムチャートに対応している。以下、ステップ毎に説明する。
【００７１】
Ｓ３０１では、ＳＢが新フォーマットに対応しているか否かを判定する。新フォーマットに対応している場合には、Ｓ３０２へ進み、新フォーマットに対応していなければＳＥロックは実行することができないので処理を終了する。
Ｓ３０２では、測光素子９の蓄積時間のタイマーを、予めＳ２０３のＳＢ通信で読み出してあるモニター発光（小）の発光時間にセットする（タイマーセット１）。
Ｓ３０３では、モニター発光（小）を指示するコマンドを送信する（モニター発光１）。ここで、１回目のモニター発光の光量は、予め規格により定めてある（例えばＩＳＯ１００のガイドナンバーで２など）のでＳＢ側に指定する必要はない。
【００７２】
Ｓ３０４では、ＳＢのモニター発光に同期して測光素子９のデータ蓄積を開始して、Ｓ３０２でセットした時間で蓄積を終了し測光データを読み出す（蓄積・読み出し１）。
Ｓ３０５では、測光データが演算に使用可能か否かを判定する。具体的には、２４０領域のＢ，Ｇ，Ｒの各データの最大値（Ｖｏｍａｘ）が所定レベル（Ｖｎ）以上にあるかどうかを判定し、所定レベル以上あれば使用可能として、２回目のモニター発光は行わずにＳ３１０へ進み、使用不可能である場合には、Ｓ３０６へ進む。
なお、通常なら最大値（Ｖｏｍａｘ）が逆に飽和レベルを超えていないかどうかの判定も必要であるが、この場合は、測光素子９の感度から実使用範囲において測光値が飽和しないようなモニター発光の光量を定めてあるのでここでは必要ない。０〜４Ｖの出力範囲を持った測光素子の場合、例えばＶｎ＝０．５Ｖ程度である。
【００７３】
Ｓ３０６では、最大値（Ｖｏｍａｘ）が所定レベルに達していなかった場合、以下に示す（式１）によって次回の発光量を算出する。
【００７４】
ＧＮ２＝ＧＮ１＋２＊ｌｏｇ２（Ｖａｇｃ／Ｖｏｍａｘ）｝　・・・（式１）
ただし、各変数は、以下の内容を示すものとする。
ＧＮ２　：次回発光量（単位：ガイドナンバー）
ＧＮ１　：前回発光量（単位：ガイドナンバー）
Ｖａｇｃ：予備測光値目標レベル（単位：Ｖ又はＡ／Ｄ値）
Ｖｏｍａｘ　：前回予備測光値の最大値（単位：Ｖ又はＡ／Ｄ値）
このように、本実施形態では、１回目の予備発光結果に応じて、２回目の予備発光光量を可変量とし、２回目の予備発光で必要かつ十分な予備発光を行うようにしている。
【００７５】
Ｓ３０７では、測光素子９の蓄積時間のタイマーを、予めＳ２０３のＳＢ通信で読み出してあるモニター発光（大）の発光時間にセットする（タイマーセット２）。
Ｓ３０８では、モニター発光（大）を指示するコマンドと光量を指定するデータを送信する（モニター発光２）。ここで、光量の指定方法は、ガイドナンバーを直接指定、前回の光量との相対値で指定、発光可能な数値を数パターンＳＢ側から通信により開示しカメラ側で最も適当な光量を選択して指定、などが考えられる。いずれの方法でも通信規格によって予め規定しておけば良い。
【００７６】
Ｓ３０９では、ＳＢのモニター発光に同期して測光素子９のデータ蓄積を開始し、Ｓ３０７でセットした時間で蓄積を終了し測光データを読み出す（蓄積・読み出し１）。
Ｓ３１０では、予備測光結果より、以下に示す（式２）を用いてＧＶ［ｉ，ｊ］（ｉ＝１〜５，ｊ＝１〜５）を算出する。ここで、ＧＶ［ｉ，ｊ］は、標準反射率被写体に対して基準露光量を与えるガイドナンバーを単位ＥＶに変換したものである。ＧＶ［ｉ，ｊ］（ｉ＝１〜５，ｊ＝１〜５）のそれぞれの位置は、図３（ａ）のＢ（１，１）〜Ｂ（５，５）に対応している。
【００７７】
ＧＶ［ｉ，ｊ］　＝　Ｌｏｇ２（ＧＮｐｒｅ＾２）＋ｌｏｇ２（ＡＤ０［ｉ，ｊ］／ＡＤ［ｉ，ｊ］）＋（ＡＶ−ＡＶ０）　・・・（式２）
ただし、各変数は、以下の内容を示すものとする。
ＧＮｐｒｅ：予備発光時のガイドナンバー（１回目もしくは２回目）
ＡＤ０［ｉ，ｊ］：適正光量時の各エリアＢ［ｉ，ｊ］（ｉ＝１〜５，ｊ＝１〜５）の測光値（エリア内の平均値）
ＡＤ［ｉ，ｊ］：予備発光時の各エリアＢ［ｉ，ｊ］（ｉ＝１〜５，ｊ＝１〜５）の測光値（エリア内の平均値）
ＡＶ：制御絞り値（ＡＰＥＸ値）
ＡＶ０：開放Ｆ値（ＡＰＥＸ値）
【００７８】
ここで、上記（式２）は、（ｉ，ｊ）の全てのエリアのＧＶ［ｉ，ｊ］を算出するための式であるが、本サブルーチンは、ＳＥロックの時の物であり、ＳＥロック時は、被写界の一部分（例えば画面中央の（３，３）のエリアなど）のみを考慮して適正光量を算出する仕様の場合もある。その場合には、ここでは、全てのＧＶ［ｉ，ｊ］を算出する必要はないので、必要とされるエリア（画面中央やＡＦエリアに対応したエリアなど）のみの算出にとどめておけば演算時間やメモリの節約になる。Ｓ３１１では、ＳＥロック実行中であることを示すフラグＳＥＬに１を代入する。
【００７９】
図１６は、予備発光２の制御内容を示したサブルーチンフローチャートである。
図１３に示したＳ１０６が実行されると本サブルーチンが呼び出されて実行される。図１３でもわかるように、本フローチャートは、ミラーアップ前の予備発光時に適用されるものであり、図１２のタイムチャートに対応している。以下、ステップ毎に説明する。
【００８０】
Ｓ４０１では、ＳＥＬ＝１か否か、すなわちＳＥロック中か否かを判定し、ＳＥロック中であれば既にＧＶ［ｉ，ｊ］が算出済みであるので処理を終了する。
Ｓ４０２では、ＳＢが新フォーマットへ対応しているか否かを判定する。新フォーマットへ対応していなければミラーアップ前の予備測光はできないので処理を終了する。
Ｓ４０３では、カスタム設定部３８の設定の一つであるカスタム設定に応じて、測光素子９による予備測光が選択されているか否かを判定する。測光素子９が選択されていない場合、つまり調光素子１５による予備測光が選択されている場合には、ミラーアップ前の予備測光はできないので処理を終了する。
【００８１】
Ｓ４０４では、測光素子９の蓄積時間のタイマーを、予めＳ２０３のＳＢ通信で読み出してあるモニター発光（小）の発光時間にセットする（タイマーセット１）。
Ｓ４０５では、モニター発光（小）を指示するコマンドを送信する（モニター発光１）。ここで、１回目のモニター発光の光量は、予め規格により定めてある（例えばＩＳＯ１００のガイドナンバーで２など）のでＳＢ側に指定する必要はない。
Ｓ４０６では、ＳＢのモニター発光に同期して測光素子９のデータ蓄積を開始、Ｓ３０２でセットした時間で蓄積を終了し測光データを読み出す（蓄積・読み出し１）。
【００８２】
Ｓ４０７では、測光データが演算に使用可能か否かを判定する。具体的には、２４０領域のＢ，Ｇ，Ｒの各データの最大値（Ｖｏｍａｘ）が所定レベル（Ｖｎ）以上にあるかどうかを判定し、所定レベル以上あれば使用可能として、２回目のモニター発光は、行わずにＳ４１２へ進み、使用不可能である場合には、Ｓ４０８へ進む。
なお、通常なら最大値（Ｖｏｍａｘ）が逆に飽和レベルを超えていないかどうかの判定も必要であるが、この場合は、Ｓ３０５同様、測光素子９の感度から実使用範囲において測光値が飽和しないようなモニター発光の光量を定めてあるのでここでは必要ない。０〜４Ｖの出力範囲を持った測光素子の場合、例えばＶｎ＝０．５Ｖ程度である。
【００８３】
Ｓ４０８では、最大値（Ｖｏｍａｘ）が所定レベルに達していなかった場合、前述の（式１）によって次回の発光量を算出する。
Ｓ４０９では、測光素子９の蓄積時間のタイマーを、予めＳ２０３のＳＢ通信で読み出してあるモニター発光（大）の発光時間にセットする（タイマーセット２）。
Ｓ４１０では、モニター発光（大）を指示するコマンドと光量を指定するデータを送信する（モニター発光２）。具体的な方法は、Ｓ３０８と同様である。
Ｓ４１１では、ＳＢのモニター発光に同期して測光素子９のデータ蓄積を開始、Ｓ４０９でセットした時間で蓄積を終了し測光データを読み出す（蓄積・読み出し２）。
Ｓ４１２では、予備測光結果より、前述の（式２）を用いてＧＶ［ｉ，ｊ］　　（ｉ＝１〜５，ｊ＝１〜５）を算出する。
【００８４】
図１７は、予備発光３の制御内容を示したサブルーチンフローチャートである。
図１３に示したＳ１０８が実行されると本サブルーチンが呼び出されて実行される。図１３でもわかるように、本フローチャートは、ミラーアップ後の予備発光時に適用されるものであり、図８、図９、図１０、又は図１１のタイムチャートに対応している。以下、ステップ毎に説明する。
Ｓ５０１では、ＳＥＬ＝１であるか否か、すなわちＳＥロック中か否かを判定し、ＳＥロック中であれば既にＧＶ［ｉ，ｊ］が算出済みであるので処理を終了する。Ｓ５０２では、ＳＢが新フォーマットへ対応しているか否かを判定する。新フォーマットへ対応していなければ、Ｓ５０３へ進み、旧フォーマットによる予備測光である予備測光４サブルーチン（図１８）を実行する。
【００８５】
Ｓ５０４では、カスタム設定部３８の設定の一つであるカスタム設定に応じて、調光素子１５による予備測光が選択されているか否かを判定する。調光素子１５が選択されていない場合、つまり測光素子９による予備測光が選択されている場合には、既にミラーアップ前に予備測光処理が終了されているはずなので処理を終了する。
【００８６】
Ｓ５０５では、調光素子１５のＩＣゲイン設定を行う（ＩＣゲイン設定１）。ゲインは、図６の領域Ｓ１〜Ｓ５について、それぞれ別々に設定される。まず、以下の（式３）に基づいてゲイン設定パラメータＧａＶ［ｉ］　（ｉ＝１〜５）を算出する。
【００８７】
ＧａＶ［ｉ］＝ＳｖＶ＋ＧｎＶ＋ＸｍＶ＋ＡｖＶ＋ＢｖＶ［ｉ］＋ＢｏＶ＋ＲｅＶ−Ｓａ［ｉ］　　（ｉ＝１〜５）　・・・（式３）
ここで、ＧａＶ［ｉ］の単位は、ＥＶであり、ｉの数値は、それぞれ領域Ｓの番号に対応している。
また、ＧａＶ［ｉ］の値が大きくなるほど高いゲインが設定される。
以下、（式３）の右辺のそれぞれの項について説明する。
【００８８】
ＳｖＶは、撮像素子の設定感度による変化量である。図１９（ａ）に示すように、感度（ＳＶ）が上がるに連れてＳｖＶも大きくなりゲインが上がる。これは、感度が高くなると適正露光を与え得る距離が遠方側に伸びるため、予備発光測光も遠方まで対応させるためである。しかし、感度が高くても近距離での撮影が行われる場合もあるので、あまり感度を上げすぎないよう感度１ＥＶの変化に対してＳｖＶの値は、１以下になるよう調整されている。
【００８９】
ＧｎＶは、予備発光１発当たりの光量（ＧＮｐ１）による変化量である。装着されるＳＢやＳＢ配光角によってＧＮｐ１は、変化するので、その変化分を吸収させＳＢがどの状態にあっても一定した測光値が得られるようにする為である。そのため、図１９（ｂ）に示すようにＧＮｐ１が１ＥＶ大きくなるとＧｎＶは、１ＥＶ小さくなるようになっている。
【００９０】
ＸｍＶは、距離による変化量である。どの距離にあっても一定した測光値が得られるようにする為である。そのため、図１９（ｃ）に示すように距離が１ＥＶ遠くなる（√２倍の距離）とＸｍＶも１ＥＶ大きくなるようになっている。
【００９１】
ＡｖＶは、絞り値による変化量である。どの絞り値であっても一定した測光値が得られるようにする為である。そのため、図１９（ｄ）に示すように絞り値が１ＥＶ大きくなる（暗くなる）とＡｖＶも１ＥＶ大きくなるようになっている。
【００９２】
ＢｖＶ［ｉ］は、輝度値による変化量である。周囲光の輝度が高くなると、予備発光中にも閃光測光部２２に周囲光が入ってしまい、ＳＢ反射光の積分値が十分蓄積される前にストップ信号が発生し積分が終わってしまうことがある。そのため、周囲光の輝度が高い場合には、その輝度に応じてその領域のゲインを下げておく。図２０に示すように、輝度がＢＶｏｆｓｅｔを越えたらその後輝度が１ＥＶ増す毎にゲインを１ＥＶ下げていき、下げ幅がＢｖＶｍａｘに達したらＢｖＶをそこでクリップする。
【００９３】
ＢｏＶは、ＳＢがバウンス状態にあるかないかで変わる値である。バウンスでない（通常の状態）では、０であり、バウンス時は、＋２ＥＶとする。これは、バウンス時は、天井などを介して被写体が照明されるため反射光量が少なくなるためである。
【００９４】
ＲｅＶは、予備発光がやり直しされたか否かで変わる値である。１回目の予備発光では、０であるが、１回目の予備発光で測光値が飽和してしまった場合には、この値を−３ＥＶとしてゲインを下げて２回目の予備発光を行う。
【００９５】
Ｓａ［ｉ］は、撮影レンズの種類と設定絞り値に応じて算出される補正値である。各エリア毎に補正値を求める（実験などによってあらかじめ算出式を定めておく）。
【００９６】
次に、以下に示す（式４）によって実際に調光素子１５に設定するゲインＤＡｐｒｅ［ｉ］を算出する。
【００９７】
ＤＡｐｒｅ［ｉ］＝（ｐｒｅ＿ｌｅｖｅｌ［ｉ］−ＧａＶ［ｉ］＊ｐｒｅ＿ｇａｍｍａ）＊Ｔ／Ｔｒｅｆ　（ｉ＝１〜５）　・・・（式４）
ただし、各変数は、以下の内容を示すものとする。
ｐｒｅ＿ｌｅｖｅｌ［ｉ］：予備発光調光レベルの基準値
ｐｒｅ＿ｇａｍｍｍａ：ガンマ調整値
Ｔ：現在の温度
Ｔｒｅｆ：調整時の温度
なお、ＧａＶ［ｉ］とマイナスになっているのは、図７に示した調光素子１５のＤＡ端子電圧を低くするとゲインが高くなる仕様のためである。
【００９８】
Ｓ５０６では、モニター発光（小）を指示するコマンドを送信する（モニター発光１）。ここで、１回目のモニター発光の光量は、予め規格により定めてある（例えばＩＳＯ１００のガイドナンバーで２など）のでＳＢ側に指定する必要はない。
Ｓ５０７では、ＳＢのモニター発光に同期して調光素子１５の積分を開始し、予めＳ２０３のＳＢ通信で読み出してあるモニター発光（小）の発光時間にてタイマーを作動させ積分を終了し、測光データＡＤ［ｉ］（ｉ＝１〜５）を読み出す（蓄積・読み出し１）。
【００９９】
Ｓ５０８では、測光データＡＤ［ｉ］（ｉ＝１〜５）が演算に使用可能か否かを判定する。具体的には、５領域のＡＤ［ｉ］データの最大値（ＡＤｍａｘ）が使用可能レベル（ＡＤ１）以上であり、かつ最大値（ＡＤｍａｘ）が飽和レベル（ＡＤ２）を越えていないかを判定する。０〜４Ｖの出力を持った調光素子の場合、例えばＡＤ１＝０．５Ｖ、ＡＤ２＝３．７Ｖ程度である。データが使用可能な場合には、２回目のモニター発光は、行わずにＳ５１３へ進み、データが使用不可能な場合は、Ｓ５０９へ進む。
【０１００】
Ｓ５０９では、Ｓ５０８の判定で、ＡＤｍａｘ＜ＡＤ１であった場合、以下の（式５）によって次回の発光量を算出し、かつ調光素子１５のゲイン設定は、Ｓ５０５と同様とする。
【０１０１】
ＧＮ２＝ＧＮ１＋｛２＊ｌｏｇ２（ＡＤａｇｃ／ＡＤｍａｘ）｝　・・・（式５）
ただし、各変数は、以下の内容を示すものとする。
ＧＮ２：次回発光量（単位：ガイドナンバー）
ＧＮ１：前回発光量（単位：ガイドナンバー）
ＡＤａｇｃ：予備測光値目標レベル（単位：Ｖ又はＡ／Ｄ値）
ＡＤｍａｘ：前回測光値の最大値（単位：Ｖ又はＡ／Ｄ値）
また、ＡＤｍａｘ＞ＡＤ２であった場合には、上述のＳ５０５の（式３）の説明にあるようにＲｅＶに−３ＥＶを代入してゲインを再計算し、かつ次回発光量は、Ｓ５０６と同様とする。
【０１０２】
Ｓ５１０では、Ｓ５０９で求めた調光素子１５のＩＣゲイン設定を行う（ＩＣゲイン設定２）。
Ｓ５１１では、Ｓ５０９で求めた発光量にてモニター発光を指示するコマンドと光量を指定するデータを送信する。具体的な方法は、Ｓ３０８と同様である。Ｓ５１２では、ＳＢのモニター発光に同期して調光素子１５の積分を開始し、予めＳ２０３のＳＢ通信で読み出してあるモニター発光の発光時間にてタイマーを作動させ積分を終了し、測光データＡＤ［ｉ］（ｉ＝１〜５）を読み出す（蓄積・読み出し２）。
Ｓ５１３では、予備測光結果より、前述の（式２）を用いてＧＶ［ｉ］（ｉ＝１〜５）を算出する。
【０１０３】
図１８は、予備発光４の制御内容を示したサブルーチンフローチャートである。
図１７のＳ５０３が実行されると本サブルーチンが呼び出されて実行される。本フローチャートは、旧フォーマットに適用されるものであり、図８、又は図９のタイムチャートに対応している。以下、ステップ毎に説明する。
【０１０４】
Ｓ６０１では、Ｓ５０５と同様の手法によって調光素子１５に設定するゲインＤＡｐｒｅ［ｉ］を算出する（ゲイン設定１）。
Ｓ６０２では、カラ打ちを２回行う。
Ｓ６０３では、ｔｒｐｅ計時開始。ＩＳ＝Ｌとして積分を開始する。
Ｓ６０４では、予備発光の小回数を示す変数Ｑｐｒｅに０をセットする。
Ｓ６０５では、Ｑｐｒｅに１を加算する。
Ｓ６０６では、発光量ＧＮｐ１で小発光（チョップ発光）を行う。
【０１０５】
Ｓ６０７では、ストップ信号が出たか否かを判定し、ストップ信号が出た場合には、Ｓ６９０へ進み、ストップ信号が出ていない場合は、Ｓ６０８へ進む。
Ｓ６０８では、小発光数が最大値として設定されたＱｐｒｅ＿ｍａｘ回に達したか否かを判定し、達している場合には、Ｓ６０９へ進み、達していない場合には、Ｓ６０５へ戻る。
【０１０６】
Ｓ６０９では、ｔｐｒｅ計時を終了する。
Ｓ６１０では、積分値ＩＧｐｒｅ［ｉ］を読み出す。
Ｓ６１１では、積分時間タイマーをｔｐｒｅにセット。
Ｓ６１２では、Ｓ６０３と同一ゲインにてｔｐｒｅ間だけ積分し、その積分値ＩＧｔｅｉ［ｉ］を読み出す。
Ｓ６１３では、予備測光結果より、前述の（式２）を用いてＧＶ［ｉ］（ｉ＝１〜５）を算出する。
【０１０７】
ここで、本発光量の演算について説明する。
まず、予備発光により得られた各領域のＧＶ［ｉ］又はＧＶ［ｉ，ｊ］を用いて、各領域の被写体反射率ＲｅＳＥＶ［ｉ］、又はＲｅＳＥＶ［ｉ，ｊ］を、以下に示す（式６）を用いて算出する。（ただし、以降は、［ｉ，ｊ］を省略し［ｉ］で代表させる。）
ＲｅＳＥＶ［ｉ］＝２＊Ｘ＋ＡＶ−ＧＶ［ｉ］　　（ｉ＝１〜５）　・・・（式６）
Ｘ：撮影距離（単位：ｍ）
ＡＶ：撮影絞り値（単位：ＡＶ）
ここで、ＲｅＳＥＶ［ｉ］は、反射率が標準値であった場合は０、反射率が標準よりも＋１段高かった場合は＋１、同様−１段では−１となる変数である。
【０１０８】
次に、ＲｅＳＥＶ［ｉ］を用いて、反射率に応じた各領域に対する重み付け数ＲｅｆＧ［ｉ］を（式７）を用いて算出する。
ＲｅｆＧ［ｉ］＝１／（２＾（Ａｂｓ（ＲｅｆＧ［ｉ］）））　（ｉ＝１〜５）　・・・（式７）
ただし、Ａｂｓ（）は、（）内の絶対値を求める関数である。ＲｅｆＧ［ｉ］は、図２１（ａ）に示すように被写体の反射率が標準値の場合には１、また標準値からから離れるに従って小さくなっていく変数である。
【０１０９】
次に、（式８）によりＲｅｆＧ［ｉ］を規格化し、各領域対する重みｗｔ［ｉ］を算出する。
ｗｔ［ｉ］＝ＲｅｆＧ［ｉ］／Σ（ＲｅｆＧ［ｉ］）　（ｉ＝１〜５）　・・・（式８）
ただし、Σ（）は、（）内の変数ＲｅｆＧ［ｉ］（ｉ＝１〜５）の総和を求める関数である。
【０１１０】
次に、（式６）で求めたＲｅＳＥＶ［ｉ］を再び用いて、（式９）により被写界全体での反射率補正値ＲｅｆＭａｉｎを算出する。
ＲｅｆＭａｉｎ＝ｌｏｇ２（Σ（ｗｔ［ｉ］＊２＾ＲｅＳＥＶ［ｉ］））　（ｉ＝１〜５）　・・・（式９）
ただし、Σ（）は、（式８）と同様の関数、ｌｏｇ２は、２の対数を表す関数である。
ＲｅｆＭａｉｎを用いて、本発光量補正値ｄｅｌｔａＹを（式１０）により算出する。
ｄｅｌｔａＹ＝ｋｒｍ＊ＲｅｆＭａｉｎ　　・・・（式１０）
【０１１１】
反射率とｄｅｌｔａＹの関係を図２１（ｂ）に示す。ここで、ｋｒｍは、反射率の補正度合いを調節する定数でありｋｒｍ＝０．５程度の数値を用いるが、必要に応じて変更可能にしても良い。
【０１１２】
Ｄ−ＴＴＬ制御の場合は、ｗｔ［ｉ］，ｄｅｌｔａＹなどを用いて（式１１）（式１２）によって本発光量倍数Ｋｇｎを算出する。ここで、本発光量倍数Ｋｇｎは、Ｓ１１２の演算結果に対応するものである。
Ｋ＝Σ（２＾（ＧＶ［ｉ］）＊ｗｔ［ｉ］）／（ＧＮｐｒｅ＾２）　・・・（式１１）
ただし、
ＧＶ［ｉ］：演算に用いるエリアのＧＶ値
ｗ［ｉ］：演算に用いるエリアの重み係数
ＧＮｐｒｅ：予備発光時ガイドナンバー
例えばＳＥロックの場合には、ＧＶ［ｉ］は、ＧＶ［３，３］のみを用い、ｗ［３，３］＝１とする。
本発光量倍数値Ｋｇｎは、以下のようにして求まる。
Ｋｇｎ＝１２＊（ｌｏｇ２（Ｋ））＋ｄｅｌｔａＹ）＋１２８　・・・（式１２）
【０１１３】
リアルタイム調光制御の場合には、ｗｔ［ｉ］，ｄｅｌｔａＹなどを用いて以下のＳａＶ［ｉ］、ＤＡｈｏｎ［ｉ］を算出する。ここで、本発光時の各エリアのＩＣゲインＤＡｈｏｎ［ｉ］は、Ｓ１１１の演算結果に対応するものである。
まず、（式１３）により各エリアのＳａＶ［ｉ］を算出する。
ＳａＶ［ｉ］　＝　ＳＶ　＋ｌｏｇ２（Ｗｔ［ｉ］）　−　ｄｅｌｔａＹ　　・・・（式１３）
ここで、
ＳＶ：フィルムの感度値（ＡＰＥＸ値）
Ｗｔ［ｉ］：各領域への重み係数
ｄｅｌｔａＹ：調光補正値
【０１１４】
次に、（式１４）により各エリアのＩＣゲインＤＡｈｏｎ［ｉ］を算出する。
ＤＡｈｏｎ［ｉ］　＝（ｈｏｎ＿ｌｅｖｅｌ［ｉ］−ＳａＶ［ｉ］＊ｈｏｎ＿ｇａｍｍａ）＊Ｔ／Ｔｒｅｆ（ｉ＝１〜５）　・・・（式１４）
ここで、
ｈｏｎ＿ｌｅｖｅｌ［ｉ］：調光レベルの基準値
ｈｏｎ＿ｇａｍｍｍａ：ガンマ調整値
Ｔ：現在の温度
Ｔｒｅｆ：調整時の温度
なお、−ＳａＶ［ｉ］とマイナスになっているのは、図７に示した調光素子１５のＤＡ端子電圧を低くするとゲインが高くなる仕様のためである。
【０１１５】
本実施形態によれば、閃光の測光を行うセンサを、必要に応じて測光素子９及び調光素子１５から選択可能としたので、ＳＥロック機能を備えつつ、ＳＥロック以外の撮影や、撮影者の希望等によって予備発光と本発光の時間間隔が目立たない動作を行うことができる。
また、新フォーマットの予備発光時には、１回目の予備発光の結果に応じて、２回目の予備発光の光量を可変としたので、予備発光に消費するエネルギを最小に押さえつつ、正確な予備測光値を得ることができる。
【０１１６】
（変形形態）
以上説明した実施形態に限定されることなく、種々の変形や変更が可能であって、それらも本発明の均等の範囲内である。
本実施形態において、ＣＣＤ等の撮像素子を用いた電子スチルカメラを例にして説明したが、これに限らず、例えば、銀塩フィルムを露光するカメラにも同様に適用することができる。
【０１１７】
【発明の効果】
以上詳しく説明したように、本発明によれば、以下の効果を奏することができる。
（１）予備発光の測光を第１閃光測光部と第２閃光測光部とのいずれで行うかを選択する予備測光選択部を備えたので、必要に応じて最適な予備発光を行うことができる。
【０１１８】
（２）、第１閃光測光部のセンサは、定常光の輝度を測光する定常光測光部のセンサを兼用し、第２閃光測光部のセンサは、本発光の発光中に本発光の被写体反射光を測光して調光を行う閃光調光部のセンサを兼用するので、既存のセンサを有効に利用することができる。
【０１１９】
（３）予備測光選択部によって第１閃光測光部が選択された場合には、予備発光をミラーアップ前に行い、第２閃光測光部が選択された場合には、予備発光をミラーアップ後に行うので、閃光測光部の配置位置に合った制御を行うことができる。
【０１２０】
（４）撮影前に予備発光を単独で行う第１の予備発光モードが実行された場合には、第１閃光測光部を選択し、撮影時に予備発光と本発光とを連続的に行う第２の予備発光モードが実行された場合には、第２閃光測光部を選択するので、ＳＥロックとリアルタイム調光とを両立させることができる。
【０１２１】
（５）予備測光選択部は、装着された閃光発光部に応じて予備発光の測光を第１閃光測光部と第２閃光測光部とのいずれで行うかを選択するので、どのような閃光発光部が装着された場合であっても、正しく予備発光を行うことができる。
【０１２２】
（６）予備発光の測光を第１閃光測光部と第２閃光測光部とのいずれで行うかに関わらず、同一の制御方式により閃光発光部へ予備発光の指示を行う予備発光制御部を備えるので、システムを簡素化することができる。
【０１２３】
（７）予備発光制御部が行う予備発光の制御方式は、所定光量の第１予備発光を行わせた後に、必要に応じて第２予備発光を行わせる方式であるので、いずれの閃光測光部であっても、確実に予備測光を行うことができる。
【０１２４】
（８）閃光発光部に所定光量の第１予備発光を行わせた後に、必要に応じて光量可変の第２予備発光を行わせる予備発光制御部と、第１予備発光時の閃光測光部の出力に応じて第２予備発光の必要性を判定する予備発光判定部とを備えるので、予備発光に消費するエネルギを最小に押さえつつ、正確な予備測光値を得ることができる。
【０１２５】
（９）予備発光制御部は、第１予備発光時の閃光測光部の出力に応じて第２予備発光の光量を算出するので、第２予備発光の光量を最適な光量で発光することができる。
【０１２６】
（１０）予備発光制御部は、第１予備発光を行う時は、予備発光を指示する情報のみを通信し、第２予備発光を行う時は、予備発光を指示する情報と発光量情報とを通信するので、余計な通信をすることなく、動作を高速にすることができる。
【０１２７】
（１１）閃光発光部は、予備発光に同期した同期信号を発生し、閃光測光部は、同期信号に同期させて測光を行うので、必要な閃光のみを測光することができる。
【図面の簡単な説明】
【図１】本発明の実施形態の光学系を示した図である。
【図２】本実施形態におけるカメラ本体３０，レンズ本体４０，ＳＢ本体５０の構成を示すブロック図である。
【図３】測光素子９の測光領域を説明する図である。
【図４】測光素子９の動作を説明する図である。
【図５】焦点検出部１６を説明する図である。
【図６】閃光測光部３３の光学系と測光領域の分割形状を示した図である。
【図７】調光素子１５を説明する図である。
【図８】旧フォーマットの予備発光によるリアルタイムＴＴＬ調光の基本動作をわかりやすく説明したタイミングチャートである。
【図９】旧フォーマットの予備発光によるＧＮ制御方式のＴＴＬ調光（以後、Ｄ−ＴＴＬ調光と呼ぶ）の基本動作をわかりやすく説明したタイミングチャートである。
【図１０】新フォーマットの予備発光によるリアルタイムＴＴＬ調光の基本動作をわかりやすく説明したタイミングチャートである。
【図１１】新フォーマットの予備発光によるＤ−ＴＴＬ調光の基本動作をわかりやすく説明したタイミングチャートである。
【図１２】新フォーマットの予備発光を行い、かつ、測光素子９を用いた予備測光方式の基本動作をわかりやすく示したタイミングチャートである。
【図１３】カメラマイコン３１のプログラムを示したフローチャートである。
【図１４】撮影前処理の制御内容を示したサブルーチンフローチャートである。
【図１５】予備発光１の制御内容を示したサブルーチンフローチャートである。
【図１６】予備発光２の制御内容を示したサブルーチンフローチャートである。
【図１７】予備発光３の制御内容を示したサブルーチンフローチャートである。
【図１８】予備発光４の制御内容を示したサブルーチンフローチャートである。
【図１９】本実施形態による閃光制御装置の各種パラメータを説明する図である。
【図２０】ＢｖＶ［ｉ］とＢＶ［ｉ］との関係を示す図である。
【図２１】ＲｅｆＧ［ｉ］及びｄｅｌｔａＹを説明する図である。
【図２２】従来技術を説明する図である。
【図２３】従来技術を説明する図である。
【符号の説明】
１　撮影レンズ
２　メインミラー
３　拡散スクリーン
４　コンデンサレンズ
５　ペンタプリズム
６　接眼レンズ
７　測光用プリズム
８　測光用レンズ
９　測光素子
１０　絞り
１１　シャッター
１２　撮像素子
１３　サブミラー
１４　調光用レンズ
１５　調光素子
１６　焦点検出部
１７　閃光発光部
１８　発光モニター部
３０　カメラ本体
３１　カメラマイコン
３２　定常光測光部
３３　閃光測光部
３４　レンズ駆動部
３５　絞り制御部
３６　感度設定部
３７　レリーズスイッチ
３８　カスタム設定部
４０　撮影レンズ本体
４１　レンズマイコン
４２　距離エンコーダ
５０　ＳＢ本体
５１　ＳＢマイコン[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flash control device that optimally controls a flash emission amount.
[0002]
[Prior art]
A flash control device that automatically adjusts a flash light emitter (hereinafter, referred to as an SB), which has been mainly used in single-lens reflex cameras, is a so-called real-time TTL dimming method. This is because, as shown in FIG. 22B, the light emitted from the flash light emitting section 17 and the light flux reflected from the subject is imaged on the imaging section 12 such as a photographic film through the photographic lens 1 and the reflected light is flashed. The photometry unit 15 performs photometry in real time, and stops the SB emission when the emission amount reaches an appropriate amount. Since this method measures light passing through a photographing lens, the method is particularly excellent in that there is no shift (parallax) between the area to be photographed and the area to be measured and that the photographer can freely set the aperture value. ing.
[0003]
However, in the real-time TTL light control method, if the reflectance of the imaging unit 12 such as a photographic film changes depending on the film to be used, an error occurs in the control amount, or the imaging unit 12 is made of an electronic device such as an electronic camera. For this reason, there is a disadvantage that the control becomes impossible if the reflectance is extremely low.
[0004]
Therefore, an apparatus which does not have the above-mentioned disadvantage is proposed in Japanese Patent Application Laid-Open No. 9-33992. As shown in FIG. 22 (a), the flash light emitting unit 17 first emits preliminary light before photographing, and the reflected light is photometrically measured through the photographing lens 1, mirror 3, screen 4, pentaprism 5, and photometric lens 8. Photometry is performed by the element 9 (hereinafter, photometry during preliminary light emission is referred to as preliminary photometry). The optimum main light emission amount is calculated based on the photometric value, and based on the result, the main light emission is controlled to the optimum light amount while monitoring the light amount by the light emission monitor unit 18a or 18b in the flash light emitter 50. In this method, since the photometry is performed without the reflection of the imaging unit, the reflectance of the imaging unit changes, and even a device having a low reflectance such as an electronic camera can be controlled without any problem.
[0005]
Further, as an apparatus for calculating the main light emission amount based on the preliminary light emission, there is an apparatus described in Japanese Patent No. 3171163. This is because, as shown in FIG. 23, the imaging output when light is emitted by the pre-emission instruction means 112 is determined by the light quantity determination means 113, and if appropriate, the imaging output at that time is recorded by the recording instruction means 116 as it is. However, when the main light emission is not appropriate, the main light emission amount is calculated by the appropriate light amount determination means 114, and the main light emission is performed by the main light emission instruction means 115.
Further, the apparatus disclosed in Japanese Patent Application Laid-Open No. 11-183978 by the present applicant repeats monitor light emission as preliminary light emission of a specified light amount and performs control so that the photometric value becomes appropriate (see FIGS. 8 and 9 described later). ).
[0006]
[Problems to be solved by the invention]
In the apparatus shown in FIG. 22A, it is necessary to perform preliminary light emission before photographing due to the principle of control. However, since the photometry is performed by the photometric element 9 on the pentaprism side, the preliminary light emission is performed by mirror-down. Must be done in state. However, since the mirror-up takes a certain time, it is necessary to emit the preliminary light emission and the main light emission at a time interval. In this case, there is a problem in that the preliminary light emission appears to be separated from the main light emission, giving a sense of incongruity to the photographer, or the model reacts to the preliminary light emission and closes the eyes during the main light emission.
[0007]
On the other hand, in the device shown in FIG. 22 (b), even when the preliminary light emission is performed, it can be performed after the mirror-up, which takes a relatively long time, so that the time lag with the main light emission is only a short time during the opening of the shutter 11. Therefore, the problem as in the device shown in FIG. However, the apparatus shown in FIG. 22B has a problem of a control error due to the difference in reflectance as described above.
By the way, as one method of flash control, a so-called SE (Speedlight Exposure) in which only the preliminary light emission is executed in advance to determine and store the main light emission amount, and thereafter the control is performed with the stored main light emission amount even if the framing is changed. There is a lock system, but if this is performed with the device shown in FIG. 22B, the mirror will be raised to perform pre-flash photometry, making the viewfinder invisible and making it impossible to readjust framing. There was a problem.
[0008]
Further, in order to calculate an accurate reflectance of a subject, an accurate photometric value at the time of preliminary light emission is necessary, and in the apparatus of Japanese Patent No. 3171163 that performs only one preliminary light emission, an accurate reflectance of the subject is used. Cannot be calculated, and therefore, there is a problem that it is not possible to perform flash light emission with an optimum light emission amount.
Further, in the apparatus disclosed in JP-A-11-183978, it is possible to obtain an accurate photometric value at the time of preliminary light emission, but as the number of times of light emission increases, the ratio of the energy actually emitted to the energy consumed at the time of light emission decreases, There was a problem that energy efficiency deteriorated.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a flash control device which has an SE lock function and is capable of performing an operation in which the time interval between the preliminary light emission and the main light emission is inconspicuous by photographing other than the SE lock or by the photographer's request. .
Another object of the present invention is to provide a flash control device capable of obtaining an accurate preliminary photometric value while minimizing the energy consumed for preliminary light emission.
[0010]
[Means for Solving the Problems]
The present invention solves the above problem by the following means. In addition, in order to facilitate understanding, the description will be given with reference numerals corresponding to the embodiment of the present invention, but the present invention is not limited to this. That is, the first aspect of the present invention is a flash control device for controlling a flash light emitting unit (17) for performing preliminary light emission and main light emission, wherein first flash light metering measures subject reflected light of the preliminary light emission by the flash light emitting unit. Unit (9), a second flash metering unit (15) for measuring the subject reflected light of the preliminary light emission by the flash light emitting unit using a sensor different from the first flash light metering unit, A flash control device comprising: a first flash metering unit and a preliminary metering selecting unit (31, 38, S103 to S106) for selecting one of the two flash metering units.
[0011]
According to a second aspect of the present invention, in the flash control device according to the first aspect, the sensor of the first flash metering section (9) also serves as a sensor of a stationary light metering section that measures brightness of the steady light. (2) A flash control device characterized in that the sensor (15) of the flash light metering section also functions as a sensor of a flash light metering section that performs light control by measuring the subject reflected light of the main light emission during the main light emission. is there.
[0012]
According to a third aspect of the present invention, in the flash control device according to the first or second aspect, the device including the flash control device is a camera including a quick return mirror (2), and 31, 38, S103 to S106), when the first flash photometer (9) is selected, preliminary light emission is performed before mirror up, and when the second flash photometer (15) is selected. Is a flash control device characterized in that preliminary light emission is performed after mirror up.
[0013]
According to a fourth aspect of the present invention, in the flash control device according to any one of the first to third aspects, a first preliminary light emission mode (SEL) in which preliminary light emission is performed independently before photographing, A second preliminary light emission mode in which preliminary light emission and main light emission are continuously performed, wherein the preliminary light measurement selection unit (31, 38, S103 to S106) performs the first preliminary light emission mode The first flash metering section (9) is selected, and the second flash metering section (15) is selected when the second preliminary flash mode is executed. It is a control device.
[0014]
According to a fifth aspect of the present invention, in the flash control device according to any one of the first to fourth aspects, the flash light emitting unit (17) is detachable from a device (30) including the flash control device. The preliminary light metering selector (31, 38, S103 to S106) performs preliminary light metering according to the flash light emitter mounted on the first flash light meter (9) and the second flash light meter. (15) to select which of the following:
[0015]
According to a sixth aspect of the present invention, in the flash control device according to any one of the first to fifth aspects, the photometry of preliminary light emission is performed by the first flash photometry section (9) and the second flash photometry section ( 15) irrespective of which one is performed, a preliminary light emission control unit (31) for instructing the flash light emission unit (17) to perform preliminary light emission by the same control method (S104, S106, S108); Which is a flash control device.
[0016]
According to a seventh aspect of the present invention, in the flash control device according to the sixth aspect, a control method of the preliminary light emission performed by the preliminary light emission control unit (31) is such that the flash light emission unit (17) has a predetermined amount of first preliminary light emission. (S303, S405, S506), and then, if necessary, the second preliminary light emission (S308, S410, S511).
[0017]
The invention according to claim 8 is a flash control device for controlling a flash light emitting section (17) for performing preliminary light emission and main light emission, wherein: a flash light meter section (9, 15) for measuring the reflected light of the subject of the preliminary light emission; A preliminary light emission control unit that causes the flash light emitting unit to perform a first preliminary light emission of a predetermined light amount (S303, S405, S506) and then performs a second preliminary light emission (S308, S410, S511) with a variable light amount as necessary. (31) and a preliminary light emission determination unit (S305, S407, S508) for determining the necessity of the second preliminary light emission in accordance with the output of the flash photometry unit at the time of the first preliminary light emission. This is a flash control device.
[0018]
According to a ninth aspect of the present invention, in the flash control device according to the eighth aspect, the preliminary light emission control unit (31) is configured to control the flash light measurement units (9, 15) during the first preliminary light emission (S303, S405, S506). ) Calculates the amount of light of the second preliminary light emission (S308, S410, S511) according to the output of the flash control device.
[0019]
According to a tenth aspect of the present invention, in the flash control device according to the eighth or ninth aspect, the preliminary light emission control unit (31) performs preliminary light emission when performing the first preliminary light emission (S303, S405, S506). When performing the second preliminary light emission (S308, S410, S511), the communication section (S308, S410, S511) communicates information for instructing preliminary light emission and light emission amount information. A flash control device.
[0020]
According to an eleventh aspect of the present invention, in the flash control device according to any one of the eighth to tenth aspects, the flash light emitting unit (17) is detachable from a device (30) including the flash control device. Wherein the flash light emitting section generates a synchronization signal synchronized with the preliminary light emission, and the flash light metering section (9, 15) performs light measurement in synchronization with the synchronization signal. It is.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings and the like.
FIG. 1 is a diagram illustrating an optical system according to an embodiment of the present invention.
The flash control device according to the present embodiment is mounted on the camera body 30 in which the photographing lens body 40 is replaceable, and controls the flash emission by the SB body 50.
[0022]
In a situation where the SB (flashlight) does not emit light except during photographing, so-called ambient light passes through the photographing lens 1 and is reflected upward by the main mirror (quick return mirror) 2 to be once formed on the diffusion screen 3. Image. Thereafter, the light reaches the eyes of the photographer through the condenser lens 4, the pentaprism 5, and the eyepiece 6. On the other hand, a part of the light flux diffused by the diffusion screen 3 is re-imaged on the photometric element 9 for stationary light through the condenser lens 4, the pentaprism 5, the photometric prism 7, and the photometric lens 8. As the photometric element 9, for example, a light receiving element such as a CCD (charge coupled device) is used, and the object field is divided into 240 × 20 areas as shown in FIG. Photometry and output the respective photometric values. Each area has photometric cells of three colors of R (red), G (green), and B (blue) as shown in FIG. 3B, and can be separated into the respective colors to enable photometry. .
[0023]
In the case of performing the preliminary light measurement using the SE lock or the light measuring element 9, the light measurement is performed along the same path as the above-described ambient light metering. The aperture 10 is in the open state, and the preliminary light emission by the flash light emitting unit 17 is performed with the main mirror 2 lowered. The SB reflected light is measured by the photometric element 9 in the same manner as the stationary light photometry, and the photometric timing is synchronized with the preliminary light emission. Then, only at the time of shooting, the aperture 10 is stopped down to the predetermined value, and at the same time, the main mirror 2 is flipped up. After that, when the shutter 11 is fully opened, the main light emission is performed with the light amount calculated in advance, and the image is captured by the image pickup device 12 constituted by, for example, a CCD or the like.
[0024]
When performing preliminary light measurement using the light control element 15, first, the aperture 10 is stopped down to a predetermined value, and at the same time, the main mirror 2 is flipped up. Thereafter, a light beam emitted from the flash light emitting unit 17 as preliminary light emission is reflected by the subject, and is substantially imaged on the shutter 11 by the photographing lens 1. A part of the light flux reflected and diffused by the shutter 11 is re-imaged on the light control element 15 through the light control lens 14 to perform flash photometry (preliminary photometry).
At the time of main light emission, the shutter 11 is opened, and an image is captured by the image sensor 12. The light control element 15 is composed of an SPD, a capacitor for accumulating a photocurrent from the SPD, an amplification amplifier, and the like, and is divided into five areas S1 to S5 as shown in FIG. To B5.
[0025]
The main mirror 2 is a half mirror that transmits a part of the light. A part of the transmitted light is bent downward by the sub-mirror 13 and guided to a focus detection unit 16 constituted by, for example, a CCD. I will be. The focus detection section 16 detects the focus state of the focus detection areas F1 to F5 of the object scene shown in FIG. 5, and drives the photographing lens 1 until the focus of any one of the areas becomes in focus. Which focus detection area is to be focused includes manual selection by the photographer, close selection, and the like.
The SB main body 50 has a flash light emitting unit 17 and a light emission monitor unit 18 that monitors the amount of light emitted from the SB main body 50.
[0026]
FIG. 2 is a block diagram illustrating a configuration of the camera body 30, the lens body 40, and the SB body 50 in the present embodiment.
The control inside the camera body 30 is all controlled by a camera microcomputer 31 which is a microprocessor, and the camera microcomputer 31 includes functions such as a preliminary light measurement selection unit, a main light emission amount calculation unit, a main light emission control unit, and a preliminary light emission control unit. In. Similarly, control in the lens body 40 is controlled by the lens microcomputer 41, and control in the SB body 50 is controlled by the SB microcomputer 51.
[0027]
(Photometry / exposure related)
The stationary light metering unit 32 is a circuit that divides the object field into 240 × 20 × 20 areas as shown in FIG. 3A or 3C, and performs photometry, and outputs the photometric output to the camera microcomputer 31. Is output. In the camera microcomputer 31, the output from the stationary light metering unit 32 and lens information such as the opening F value, focal length, exit pupil position, and distance information of the taking lens stored in the lens microcomputer 41 provided in the taking lens 40 are stored. Calculates an appropriate exposure value for the steady light exposure based on the sensitivity information of the image sensor 12 from the sensitivity setting unit 36, decomposes it into an aperture value and a shutter value, and outputs it to the aperture control unit 35 and the shutter 11. . The aperture control unit 35 controls aperture stop / return of the aperture 10 according to a release signal from the release switch 37.
[0028]
(Auto focus related)
The focus detection unit 16 detects the focus state for five regions of the object scene as shown in FIG. The information is processed by the camera microcomputer 31, becomes a lens drive amount, and is output to the lens drive unit 34, and further drives the lens optical system 1 in the lens body 40 to a focused state.
[0029]
(SE lock)
When detecting that the SE lock switch (not shown) is pressed, the camera microcomputer 31 causes the flash light emitting unit 17 to emit preliminary light through the SB microcomputer 51. On the other hand, the reflected light is measured by the steady light metering unit 32 in synchronization with the preliminary light emission, and a main light emission amount indication value is calculated based on the result and stored in the memory in the camera microcomputer 31. Thereafter, when the full press of the release switch 37 is detected, the main light emission amount instruction value in the memory is communicated to the SB main body 50, and then the photographing operation is performed. The SB microcomputer 51 calculates the main light emission amount from the main light emission amount instruction value and the preliminary light emission value measured by the light emission monitor unit 18 by itself, and emits light according to the light emission trigger signal (X signal) at the time of photographing. To control.
[0030]
(SB control using the light control element 15)
The camera microcomputer 31 calculates the set gain of the flash photometric unit 33 based on the photometric value, aperture value, sensitivity value, distance value, bounce state of the flash light emitting unit, and performs gain setting. After that, the flash light emitting section 17 is preliminarily emitted from the camera microcomputer 31 through the SB microcomputer 51, and the flash light metering section 33 integrates a photocurrent according to the subject reflected light amount. The main light emission amount instruction value is calculated based on the integrated value, and the main light emission instruction value is output to the SB microcomputer 51 again. The SB microcomputer 51 calculates the main light emission amount from the main light emission amount instruction value and the preliminary light emission value measured by the light emission monitor unit 18 by itself, and emits light according to the light emission trigger signal (X signal) at the time of photographing. To control.
[0031]
Whether or not to perform the SB control using the light control element 15 can be selected by the custom setting unit 38. In addition, even when the light control element 15 is used, the main light emission amount is calculated and controlled as described above from the preliminary light emission result, and the light control element 15 measures light in real time during the main light emission to reach an appropriate light amount. Incidentally, a so-called real-time dimming method in which a stop signal is output from the dimming element 15 to stop the SB light can be selected. This is also selected by the custom setting unit 38.
[0032]
(SB control using photometric element 9)
The camera microcomputer 31 makes the flash light emitting unit 17 emit preliminary light through the SB microcomputer 51, and integrates the photocurrent according to the subject reflected light amount by the steady light metering unit 32. The main light emission amount instruction value is calculated based on the integrated value, and the main light emission instruction value is output to the SB microcomputer 51. The SB microcomputer 51 calculates the main light emission amount from the main light emission amount instruction value and the preliminary light emission value measured by the light emission monitor unit 18 by itself, and emits light according to the light emission trigger signal (X signal) at the time of photographing. To control.
Whether or not to perform the SB control using the photometric element 9 can be selected by the custom setting unit 38.
[0033]
FIG. 3 is a diagram illustrating a photometry area of the photometry element 9.
FIGS. 3A and 3C are diagrams showing the split state of the photometric element 9 in comparison with the object scene. The photometric element 9 is capable of dividing substantially the entire surface of the object field into 240 portions for photometry and outputting respective photometric values.
FIG. 3A shows a divided shape when 240 photometric areas are grouped into 25 areas B (1, 1) to B (5, 5).
FIG. 3C shows a shape when the photometry areas are similarly grouped into five areas B1 to B5, which are averaged according to the division shape of the flash photometry section 33.
FIG. 3B shows a state where each photometry area is divided into three color photometry areas of RGB.
[0034]
FIG. 4 is a diagram for explaining the operation of the photometric element 9.
FIG. 4A shows the terminals of the photometric element 9 and their roles. φMCK is a master clock input which is the basis of the operation of the photometric element 9. φint is an input for controlling the start and end of accumulation. VCscin is a switching input for performing unnecessary charges at the time of power-on at high speed. GSW is an input for switching the sensitivity between two levels of H / L. RSW is an input (usually fixed to one) for switching the output clock frequency of the photometric value between two stages. SYNC is a photometric value reading synchronous clock output. Vout is a photometric value output.
[0035]
FIG. 4B is a diagram illustrating an arrangement of the photoelectric conversion units of the photometric element 9. In the horizontal direction (H direction), B, G, and R are one cycle, and 20 periods, totaling 60 pixels. In the vertical direction (V direction), any of B, G, and R is arranged in 20 pixels. At the time of data output, first, one pixel is shifted in the H direction, and data for one column is transferred to the V register. Then, one column, that is, 20 pixels are output in the V direction. After that, the output for one column is repeated in the V direction after shifting another pixel in the H direction, and this is repeated until the last R column is output.
FIG. 4C is a diagram showing the data output state of the photometric element 9 in an easily understandable manner. When φint becomes L, accumulation starts, and ends when it returns to H. Thereafter, the photometric data is automatically output one by one in synchronization with the SYNC pulse.
[0036]
FIG. 5 is a diagram illustrating the focus detection unit 16.
FIG. 5A shows a detection area of the focus detection unit 16 in comparison with an object field. The focus state in five areas F1 to F5 can be respectively detected. FIG. 5B shows the optical system of the focus detection unit 16 in detail. The light beam that has passed through the photographing lens 1 passes through the field mask 16a, the field lens 16b, and the separator lens 16c, and reaches the AF sensor 16d.
[0037]
FIG. 6 is a diagram showing the optical system of the flash photometer 33 and the divided shape of the photometry area.
The subject image incident on the shutter surface and imaged is re-imaged on the dimming element 15 by the triple dimming lens 14, and divided into five areas S1 to S5 to accumulate the electric charges which are photoelectrically converted respectively. Configuration. Here, the relationship between each area of S1 to S5 and the number corresponds to the number of each area of the photometric areas B1 to B5 in FIG. Also, the aperture mask 15a cuts the incident light from the adjacent lens so that it does not enter the sensor as stray light.
[0038]
FIG. 7 is a diagram illustrating the light control element 15.
FIG. 7A shows the terminals of the light control element 15 and their roles. C1 to C5 are external capacitors for storing the photocurrents in the regions S1 to S5, respectively. SC is an external capacitor that adds and accumulates the photocurrents of S1 to S5 to output a stop signal. Vref is a temperature proportional voltage output terminal. TOP is a top signal output terminal. CSR, CSG, and CLK are terminals for switching the setting of the amplifier gain and the read channel, and the setting method will be described with reference to FIGS. 7B and 7C, respectively. IS is a terminal for starting / ending storage. DA is a terminal for inputting the amplifier gain of each area. AD is an output terminal of the photometric integrated value of each area.
[0039]
FIG. 7B shows a method of setting the amplifier / gain of each area of the light control element 15. When the CSR terminal is lowered to the L level while the CSG terminal is maintained at the H level, and then a clock signal is input to the CLK terminal, the channel is switched in synchronization with the fall to the L level. By setting the DA terminal to a voltage level according to the set gain while the CLK terminal is at the L level, the gain of the channel is set. Ch1 to Ch5 correspond to S1 to S5, respectively.
[0040]
FIG. 7C shows a method of reading the photometric integrated value of each area of the light control element 15. When a clock signal is input to the CLK terminal after the CSR and CSG terminals have been lowered to the L level, the channels are switched in synchronization with the fall to the L level, and the photometric integrated value of each area becomes a voltage level corresponding to the photometric value. Output to the AD terminal.
[0041]
FIG. 8 is a timing chart for easily explaining the basic operation of real-time TTL light control by preliminary light emission in the old format.
Here, the preliminary light emission of the old format refers to a method in which a small amount of light emission (chop light emission) of a small amount of light is repeated many times, and the preliminary light emission ends when a necessary amount of preliminary light emission is obtained.
When the release signal is input and the mirror-up and aperture stop are completed, in a phase (hereinafter, referred to as P) 8-1, a handshake between the camera and the SB is performed by the operation of the communication terminal 1 and the communication terminal 2, and the preliminary light emission sequence is started. Is performed.
Thereafter, in P8-2, the gain setting (gain setting 1) of the light control element 15 is performed. The method of calculating the gain will be described later in detail.
[0042]
Next, in P8-3, after the light emission of the small light emission is performed twice for warming up the flash light emitting section 17 and the light control element 15, the IS terminal is lowered to start integration (integration 1). At the same time, preliminary light emission is performed in synchronization with the clock of the communication terminal 2 from the camera side. Preliminary light emission ends when the photometric integrated value reaches an appropriate level or the number of small light emission reaches the maximum number (about 16 times).
[0043]
In P8-4, after the reading of the integrated value (reading 1) is performed, the IS terminal is activated to reset the integrated value. Since the integral value at the time of preliminary light emission includes not only the reflected light of the SB light but also the steady light component, only the steady light is integrated after the end of the preliminary light emission, and the steady light component is integrated in the subsequent processing in the preliminary light emission integration. Perform an operation to subtract from the value.
[0044]
In P8-5, a gain setting (gain setting 2) for integrating the steady light is performed.
After that, at P8-6, the IS terminal falls and the steady light integration (integration 2) is performed as in the case of the preliminary light emission. The gain setting and integration time of the steady light integration will be described later. When the steady light integration is completed, the integrated value is read out (readout 2) at P8-7, and the IS terminal is started up to reset the integrated value.
[0045]
Thereafter, in P8-8, the dimming area and the correction amount are calculated by an algorithm described later.
In P8-9, the main dimming gain setting for performing the main light emission control is performed based on the calculation result in P8-8.
Thereafter, in P8-10, main light control integration and main light emission are performed in synchronization with the shutter fully opened at the start of photographing, and when a proper light amount is reached, a stop signal is output, light emission is stopped, and real time light control is performed. Thereafter, at a predetermined shutter time, the shutter closes and the shooting is completed.
[0046]
FIG. 9 is a timing chart for easily explaining the basic operation of TTL light control (hereinafter, referred to as D-TTL light control) of the GN control method by preliminary light emission of the old format.
Here, the D-TTL light control refers to a method in which a main light emission amount is calculated and determined in advance before main light emission from a photometric value obtained by preliminary light emission.
In FIG. 9, steps up to P9-8 are the same as those in FIG. After calculating the dimming area and the correction amount in P9-8, in P9-9, the main light emission amount is calculated by a method described later, and the value is communicated to the flash light emitting unit 17 through the SB microcomputer 51 (the main light emission amount). Volume data communication). On the basis of the result, in P9-10, the main light emission control is performed on the SB side at the time of shooting to control the appropriate amount of light, and the shooting is completed.
[0047]
FIG. 10 is a timing chart for easily explaining the basic operation of the real-time TTL light control by the preliminary light emission of the new format.
Here, the preliminary light emission of the new format is a preliminary light emission method of a new format different from the above-described preliminary light emission of the old format, and is a method improved to increase the efficiency of the SB light emission and the preliminary light measurement. While the above-described preliminary light emission method of the old format repeats a large number of chop light emissions, the preliminary light emission of the new format performs one or two preliminary light emission operations.
[0048]
When the SB main body 50 is attached to the camera main body 30, the camera main body 30 communicates with the SB main body 50, determines whether the SB side supports the new format, and the SB supports the new format. If it is detected, the system automatically switches to preliminary photometry using the new format.
When the release signal is input and the mirror-up and aperture stop are completed, in P10-1, the start of the preliminary light emission sequence is declared from the camera body 30 by communication between the camera body 30 and the SB body 50 via the communication terminals 1 to 3. Is done.
[0049]
After that, in P10-2, the gain setting (gain setting 1) of the dimming element 15 is performed. The method of calculating the gain will be described later in detail.
Next, in P10-3, similarly, a command for instructing monitor light emission (small) is transmitted from the camera body 30 by communication between the camera body 30 and the SB body 50.
Thereafter, in P10-4, while the camera lowers the communication terminal 1 to L, the SB main body 50 performs monitor light emission (preliminary light emission) of a predetermined light amount substantially in synchronization with L of the communication terminal 2. The camera body 30 performs integration (integration 1) by lowering the IS terminal of the light control element 15 by synchronizing the L of the communication terminal 2 with the light emission synchronization signal and synchronizing with the emission synchronization signal. At the timing when the preliminary light emission ends, reading of the integrated value (reading 1) is performed.
[0050]
In P10-5, it is determined from the read integration value whether or not the level of the preliminary photometry value at this time has reached a size necessary for the calculation (the second time necessity determination). If the photometric value has not reached the required level, the flow shifts to P10-6, and if the photometric value has reached the required level, the flow shifts to P10-9.
In P10-6, the second gain setting (gain setting 2) is performed.
In P10-7, a command for instructing the monitor light emission (large) and the light emission amount (GN) is transmitted.
In P10-8, monitor light emission (large) and integration (integration 2) are performed as in the first time.
[0051]
The integral value at the time of preliminary light emission includes a steady light component in addition to the reflected light of the SB light. Therefore, in P10-9 to P10-9, after the preliminary light emission is completed, only the stationary light is integrated, and in the subsequent arithmetic processing, the operation of subtracting the stationary light component from the preliminary light emission integrated value is performed. In this case, the setting of the steady light gain and the integration time are set to the same values as the gain and the integration time set at the time of the immediately preceding integration.
When the steady light integration is completed, the end of the preliminary light emission sequence is declared by communication in P10-11.
[0052]
Thereafter, in P10-12, the dimming area and the correction amount are calculated by an algorithm described later.
In P10-13, the main light control gain setting for performing the main light emission control is performed using the result of P10-12, and the release input command is communicated in P10-14. After that, in P10-15, the main light integration and the main light emission are performed in synchronization with the shutter fully opened at the start of shooting, and when the light amount reaches an appropriate light amount, a stop signal is output, the light emission stops, and the real time light control is performed. , And FIG. Thereafter, at a predetermined shutter time, the shutter closes and the shooting is completed.
[0053]
FIG. 11 is a timing chart for easily explaining the basic operation of D-TTL dimming by preliminary light emission of a new format.
In FIG. 11, the steps up to P11-12 are the same as those in FIG.
In P11-12, after calculating the dimming area and the correction amount, the main light emission amount is calculated by a method described later, and the value is transmitted to the SB as a main light emission amount transmission command and light emission multiple data by communication. Based on the result, at the time of photographing in the same manner as in the case of FIG. 9, the main light emission control is performed on the SB side, the appropriate light amount is controlled, and the photographing is completed.
[0054]
FIG. 12 is a timing chart showing the basic operation of the preliminary photometric method using the photometric element 9 and performing the preliminary light emission of the new format.
When the release signal is input, the camera first declares the start of the preliminary light emission sequence by communication between the camera and the SB via the communication terminals 1 to 3 at P12-1 before performing mirror-up and focusing.
Next, in P12-3, a command for instructing monitor light emission (small) is transmitted from the camera side by communication between the camera and the SB.
[0055]
Thereafter, at P12-4, while the camera lowers the communication terminal 1 to L, the SB performs monitor light emission (preliminary light emission) of a predetermined light amount substantially in synchronization with L of the communication terminal 2. The camera uses L of the communication terminal 2 as a light emission synchronizing signal and synchronizes with the light emission synchronizing signal to lower the φint terminal of the photometric element 9 to accumulate data (integration 1). Reading of the photometric data (read 1) is performed at the timing when the preliminary light emission ends.
[0056]
In P12-5, it is determined whether or not the level of the preliminary photometric value at this time has reached a size necessary for calculation (the second time necessity determination). If the photometric value has not reached the required level, the process proceeds to P12-6. If the photometric value has reached the required level, the process proceeds to P12-8.
[0057]
In P12-6, a second gain setting (gain setting 2) is performed, and then a command for instructing monitor light emission (large) and its light emission amount (GN) is transmitted.
At P12-7, monitor light emission (large) and data accumulation (integration 2) are performed in the same manner as the previous monitor light emission (small).
In P12-8, the end of the preliminary light emission sequence is declared by communication.
In P12-9, the dimming area, the correction amount, and the main light emission amount are calculated by an algorithm described later.
[0058]
P12-10 is a release waiting state, and for example, in the case of SE lock, it takes a relatively long time.
In P12-11, mirror up and aperture down are performed.
In P12-12, the value calculated in P12-9 is transmitted to the SB side by communication as the main light emission amount transmission command and the light emission multiple data.
In P12-13, based on the obtained values, the main light emission control is performed on the SB side to control the appropriate amount of light at the time of shooting, as in the case of FIG. 9, and the shooting is completed.
[0059]
[Table 1]

[0060]
Table 1 is a list summarizing the relationship between the dimming control and the preliminary light emission method shown in FIGS.
In each of the dimming controls described with reference to FIGS. 8 to 11, the photometry of flash is performed by the dimming element 15, and a preliminary light emission method (old format, new format) and a dimming method (real-time TTL, D-TTL). Is the difference between the combinations. On the other hand, in the control shown in FIG. 12, flash photometry is performed using the photometry element 9. In the case of performing flash photometry using the photometry element 9, since the photometry becomes impossible when the mirror is raised, real-time TTL dimming cannot be performed.
[0061]
Regarding the method of preliminary light emission, even in the case where a photometric element is used, preliminary light emission of the old format can be performed in principle. However, in the preliminary light emission using the old format, the amount of light emission is small with respect to the time during which the flash photometry is performed. Therefore, if the ambient light is bright, the ambient light enters during a time when the light is not shining. Generally, the photometric element is more likely to saturate than the dimming element, so that if the ambient light is bright, the photometric element 9 will be saturated immediately. On the other hand, according to the preliminary light emission of the new format, photometry can be performed only during the flash light emission period, and the new format is suitable for the preliminary light emission by the photometric element 9. Further, as described above, the pre-light emission method of the old format in which chop light emission is repeated does not have very good energy efficiency.
Therefore, in the present embodiment, when the photometric element 9 is used, only preliminary light emission of a new format is performed.
[0062]
FIG. 13 is a flowchart showing a program of the camera microcomputer 31. When the release switch 37 of the camera is half-pressed, the power of the camera is turned on, and this program is executed. Hereinafter, each step (hereinafter, referred to as S) will be described.
In S101, the flag SEL for identifying the SE lock state is cleared to 0 (set to the non-SE lock state).
In S102, a pre-imaging subroutine process (described in FIG. 14) is performed.
[0063]
In S103, it is determined whether an SE lock switch (not shown) has been pressed. If the SE lock switch has been pressed, the process proceeds to S104. If the SE lock switch has not been pressed, the process proceeds to S105.
In S104, a subroutine process (preliminary light emission 1: described with reference to FIG. 15) when the SE lock switch is pressed is performed.
In S105, it is determined whether or not the release switch 37 has been fully pressed. If the release switch 37 has been fully pressed, the process proceeds to S106. If the release switch 37 has not been fully pressed, the process proceeds to S120.
[0064]
In S106, a subroutine process (preliminary light emission 2: described in FIG. 16) before mirror up is performed.
In S107, mirror up and aperture down are performed.
In S108, a preliminary light emission subroutine (preliminary light emission 3: described in FIG. 17) after mirror up is performed.
It should be noted that only one of the above-described preliminary light emission 1 to 3 and the preliminary light emission 4 in FIG. 17 described below is executed (determined in each subroutine).
[0065]
In S109, an algorithm calculation (area selection, correction amount calculation) of real-time TTL light control is performed. The details of this calculation will be described later.
In S110, it is determined whether or not the real-time dimming control by the stop signal is selected according to the custom setting which is one of the settings of the custom setting unit 38. When the real-time dimming control is selected, the process proceeds to S111, and when the real-time dimming control is not selected, the process proceeds to S112.
In S111, the gain of the dimming element 15 is set to perform real-time dimming control. This real-time dimming control corresponds to the time chart in FIG. 8 or FIG. The method of calculating the gain will be described later.
In S112, the main light emission amount calculation in the case of the D-TTL control is performed. This D-TTL control corresponds to the time chart of FIG. 9, FIG. 11, or FIG. Details of the D-TTL control will be described later.
[0066]
In S113, communication of main light emission amount data (Kgn, described later) is performed from the camera to the SB. (See FIGS. 9, 11, and 12)
In S114, the shutter is opened (photographing exposure starts).
In S115, it is determined whether or not the real-time dimming control is performed. In the case of the real-time dimming control, the process proceeds to S116, and the integration of the dimming element 15 is started. If it is not the real-time light control, the process proceeds to S117.
In S117, main light emission control is performed. In addition, this light emission control performs either real-time light control or D-TTL light control as the case may be.
In S118, the shutter is closed for a predetermined time (imaging exposure is completed), and the mirror and the aperture are returned.
In S119, the SE lock flag (SEL) is cleared to 0.
In S120, it is determined whether or not a predetermined time has elapsed after the half-press timer has been activated. If it is within the predetermined time, the process returns to step S102 to repeat the process, and if the timer has expired, the process ends.
[0067]
FIG. 14 is a subroutine flowchart showing the control contents of the pre-shooting process.
The pre-imaging process shown in FIG. 14 is executed by calling this subroutine when S102 shown in FIG. 13 is executed. Hereinafter, each step will be described.
In step S201, various settings (sensitivity, photometry mode, exposure mode, and the like) of the camera are read.
In S202, the focal length, the open F-number, the exit pupil distance, the distance data, and the like of the photographing lens are read out by lens communication.
[0068]
In step S203, the SB communication determines whether or not the SB supports the new format, the light emission time of the monitor light emission (small and large), the light amount per one chop light emission, the maximum main light emission amount, and the state of the SB (bounce state or not). Or not).
In step S204, constant light photometry is performed, and photometric values and the like of B (1,1) to B (5,5), B1 to B5 are calculated.
In step S205, an appropriate exposure value is calculated based on the photometric value by a known method, and an aperture value and a shutter value are calculated according to the exposure mode.
[0069]
In S206, focus detection is performed.
In S207, the lens is driven and focused until the defocus amount becomes 0 according to the state of focus detection.
In S208, the focus distance of the photographing lens at the in-focus position is regarded as the subject distance, and the value is read from the lens microcomputer 41.
[0070]
FIG. 15 is a subroutine flowchart showing the control content of the preliminary light emission 1.
The preliminary light emission 1 shown in FIG. 15 is executed by calling this subroutine when S104 shown in FIG. 13 is executed. As can be seen from FIG. 13, this flowchart is applied at the time of executing the SE lock, and corresponds to the time chart of FIG. Hereinafter, each step will be described.
[0071]
In S301, it is determined whether the SB supports the new format. If the new format is supported, the process proceeds to S302, and if the new format is not supported, the SE lock cannot be executed, and the process ends.
In S302, the timer of the accumulation time of the photometric element 9 is set to the light emission time of the monitor light emission (small) read out in advance in the SB communication of S203 (timer set 1).
In S303, a command for instructing monitor light emission (small) is transmitted (monitor light emission 1). Here, the light amount of the first monitor emission is determined in advance by a standard (for example, the guide number of ISO 100 is 2), so it is not necessary to specify the light amount on the SB side.
[0072]
In S304, data accumulation of the photometric element 9 is started in synchronization with the monitor light emission of the SB, and the accumulation ends at the time set in S302, and the photometric data is read (accumulation / readout 1).
In S305, it is determined whether the photometric data can be used for calculation. Specifically, it is determined whether or not the maximum value (Vomax) of each of the B, G, and R data in the 240 area is equal to or higher than a predetermined level (Vn). The process proceeds to step S310 without performing light emission, and proceeds to step S306 if the device cannot be used.
Normally, it is also necessary to determine whether the maximum value (Vomax) does not exceed the saturation level. In this case, however, the sensitivity of the photometric element 9 prevents the photometric value from being saturated in the actual use range. It is not necessary here because the amount of light emission is determined. In the case of a photometric element having an output range of 0 to 4 V, for example, Vn is about 0.5 V.
[0073]
In S306, when the maximum value (Vomax) has not reached the predetermined level, the next light emission amount is calculated by the following (Equation 1).
[0074]
GN2 = GN1 + 2 * log2 (Vagc / Vomax)｝ (Formula 1)
However, each variable indicates the following contents.
GN2: Next light emission (unit: guide number)
GN1: Previous light emission (unit: guide number)
Vagc: Preliminary photometric value target level (unit: V or A / D value)
Vomax: maximum value of the previous preliminary photometry value (unit: V or A / D value)
As described above, in the present embodiment, the amount of second preliminary light emission is made variable in accordance with the result of the first preliminary light emission, and necessary and sufficient preliminary light emission is performed in the second preliminary light emission.
[0075]
In S307, the timer of the accumulation time of the photometric element 9 is set to the light emission time of the monitor light emission (large) read in advance in the SB communication of S203 (timer set 2).
In S308, a command for instructing monitor light emission (large) and data for designating light amount are transmitted (monitor light emission 2). Here, the light amount is specified by directly specifying the guide number, specifying the guide number relative to the previous light amount, disclosing the numerical values that can emit light from the number SB side through communication, and selecting the most appropriate light amount on the camera side. Designation, etc. are conceivable. Either method may be specified in advance by a communication standard.
[0076]
In step S309, data accumulation of the photometric element 9 is started in synchronization with the SB monitor light emission, and the accumulation ends at the time set in step S307, and the photometric data is read (accumulation / readout 1).
In S310, GV [i, j] (i = 1 to 5, j = 1 to 5) is calculated from the preliminary photometry result using the following (Equation 2). Here, GV [i, j] is obtained by converting a guide number that gives a reference exposure amount to a standard reflectance subject into a unit EV. Each position of GV [i, j] (i = 1 to 5, j = 1 to 5) corresponds to B (1,1) to B (5,5) in FIG.
[0077]
GV [i, j] = Log2 (GNpre ＾ 2) + log2 (AD0 [i, j] / AD [i, j]) + (AV-AV0) (Equation 2)
However, each variable indicates the following contents.
GNpre: guide number at the time of preliminary light emission (first or second time)
AD0 [i, j]: photometric value of each area B [i, j] (i = 1 to 5, j = 1 to 5) at an appropriate light amount (average value in the area)
AD [i, j]: photometric value of each area B [i, j] (i = 1 to 5, j = 1 to 5) at the time of preliminary light emission (average value in the area)
AV: Control aperture value (APEX value)
AV0: Open F value (APEX value)
[0078]
Here, the above (Equation 2) is an equation for calculating GV [i, j] of all the areas of (i, j), but this subroutine is a thing at the time of SE lock. At the time of locking, there may be a case where an appropriate amount of light is calculated in consideration of only a part of the object scene (for example, the (3, 3) area at the center of the screen). In this case, since it is not necessary to calculate all GV [i, j] here, the calculation can be performed if only the required area (such as the center of the screen or the area corresponding to the AF area) is calculated. Saves time and memory. In S311, 1 is assigned to a flag SEL indicating that the SE lock is being executed.
[0079]
FIG. 16 is a subroutine flowchart showing the control content of the preliminary light emission 2.
When S106 shown in FIG. 13 is executed, this subroutine is called and executed. As can be seen from FIG. 13, this flowchart is applied at the time of preliminary light emission before the mirror is raised, and corresponds to the time chart of FIG. Hereinafter, each step will be described.
[0080]
In S401, it is determined whether or not SEL = 1, that is, whether or not the SE is locked. If the SE is locked, the process ends because GV [i, j] has already been calculated.
In S402, it is determined whether the SB supports the new format. If the new format is not supported, the pre-metering before the mirror-up operation cannot be performed, and the process is terminated.
In step S403, it is determined whether or not the preliminary photometry by the photometric element 9 has been selected according to the custom setting which is one of the settings of the custom setting unit 38. When the photometric element 9 is not selected, that is, when the preliminary photometry by the light control element 15 is selected, the preliminary photometry before the mirror-up operation cannot be performed, and the process is terminated.
[0081]
In S404, the timer of the accumulation time of the photometric element 9 is set to the monitor emission (small) emission time read out in advance in the SB communication of S203 (timer set 1).
In S405, a command for instructing monitor light emission (small) is transmitted (monitor light emission 1). Here, the light amount of the first monitor emission is determined in advance by a standard (for example, the guide number of ISO 100 is 2), so it is not necessary to specify the light amount on the SB side.
In S406, data accumulation of the photometric element 9 is started in synchronization with the monitor light emission of the SB, and the accumulation is completed at the time set in S302, and the photometric data is read (accumulation / readout 1).
[0082]
In S407, it is determined whether the photometric data can be used for calculation. Specifically, it is determined whether or not the maximum value (Vomax) of each of the B, G, and R data in the 240 area is equal to or higher than a predetermined level (Vn). The light emission is not performed, and the process proceeds to S412. If the light emission is not possible, the process proceeds to S408.
Normally, it is necessary to determine whether the maximum value (Vomax) does not exceed the saturation level. In this case, however, the photometric value does not saturate in the actual use range from the sensitivity of the photometric element 9 as in step S305. Since the amount of monitor light emission is determined as described above, it is not necessary here. In the case of a photometric element having an output range of 0 to 4 V, for example, Vn is about 0.5 V.
[0083]
In S408, if the maximum value (Vomax) has not reached the predetermined level, the next light emission amount is calculated by the above-described (Equation 1).
In S409, the timer of the accumulation time of the photometric element 9 is set to the emission time of the monitor emission (large) previously read out by the SB communication of S203 (timer set 2).
In S410, a command for instructing monitor light emission (large) and data for designating light amount are transmitted (monitor light emission 2). The specific method is the same as in S308.
In S411, data accumulation of the photometric element 9 starts in synchronization with the monitor light emission of the SB, and the accumulation ends at the time set in S409, and the photometric data is read (accumulation / readout 2).
In S <b> 412, GV [i, j] (i = 1 to 5, j = 1 to 5) is calculated from the preliminary photometry result using the above-described (Equation 2).
[0084]
FIG. 17 is a subroutine flowchart showing the control content of the preliminary light emission 3.
When S108 shown in FIG. 13 is executed, this subroutine is called and executed. As can be seen from FIG. 13, this flowchart is applied at the time of preliminary light emission after the mirror is raised, and corresponds to the time chart of FIG. 8, FIG. 9, FIG. 10, or FIG. Hereinafter, each step will be described.
In S501, it is determined whether or not SEL = 1, that is, whether or not SE lock is being performed. If SE lock is being performed, GV [i, j] has already been calculated, and the process ends. In S502, it is determined whether the SB supports the new format. If the new format is not supported, the process advances to step S503 to execute a preliminary photometry 4 subroutine (FIG. 18) which is a preliminary photometry using the old format.
[0085]
In S <b> 504, it is determined whether or not the preliminary light measurement by the light control element 15 is selected according to the custom setting which is one of the settings of the custom setting unit 38. If the light control element 15 is not selected, that is, if the preliminary light measurement by the light measurement element 9 is selected, the preliminary light measurement processing should have already been completed before the mirror-up operation, and thus the processing ends.
[0086]
In S505, the IC gain of the light control element 15 is set (IC gain setting 1). The gain is set separately for each of the regions S1 to S5 in FIG. First, a gain setting parameter GaV [i] (i = 1 to 5) is calculated based on the following (Equation 3).
[0087]
GaV [i] = SvV + GnV + XmV + AvV + BvV [i] + BoV + ReV-Sa [i] (i = 1 to 5) (Equation 3)
Here, the unit of GaV [i] is EV, and the numerical value of i corresponds to the number of the region S.
Also, the higher the value of GaV [i], the higher the gain is set.
Hereinafter, each term on the right side of (Equation 3) will be described.
[0088]
SvV is an amount of change due to the set sensitivity of the image sensor. As shown in FIG. 19A, as the sensitivity (SV) increases, SvV increases and the gain increases. This is because the higher the sensitivity, the longer the distance at which the proper exposure can be given extends to the far side, so that the pre-flash metering can be performed at a long distance. However, even when the sensitivity is high, there is a case where shooting is performed at a short distance, so that the value of SvV is adjusted to be 1 or less with respect to a change of the sensitivity 1EV so as not to increase the sensitivity too much.
[0089]
GnV is the amount of change due to the amount of light (GNp1) per preliminary light emission. Since GNp1 changes depending on the SB and the SB light distribution angle to be mounted, the change is absorbed so that a constant photometric value can be obtained regardless of the state of the SB. For this reason, as shown in FIG. 19B, when GNp1 increases by 1 EV, GnV decreases by 1 EV.
[0090]
XmV is the amount of change due to distance. This is to ensure that a constant photometric value can be obtained at any distance. For this reason, as shown in FIG. 19C, when the distance increases by 1 EV (√2 times the distance), XmV also increases by 1 EV.
[0091]
AvV is the amount of change due to the aperture value. This is to ensure that a constant photometric value can be obtained regardless of the aperture value. Therefore, as shown in FIG. 19D, when the aperture value increases by 1 EV (darkens), the AvV also increases by 1 EV.
[0092]
BvV [i] is a change amount due to the luminance value. If the brightness of the ambient light increases, the ambient light may enter the flash photometric unit 22 even during the preliminary light emission, and a stop signal may be generated before the integral value of the SB reflected light is sufficiently accumulated, and the integration may end. is there. Therefore, when the luminance of the ambient light is high, the gain of the area is reduced according to the luminance. As shown in FIG. 20, when the luminance exceeds BVoffset, thereafter, every time the luminance increases by 1 EV, the gain is reduced by 1 EV, and when the reduction width reaches BvVmax, BvV is clipped there.
[0093]
BoV is a value that changes depending on whether the SB is in a bounce state. The value is 0 when not bounced (normal state), and +2 EV when bounced. This is because during bounce, the subject is illuminated via a ceiling or the like, so that the amount of reflected light is reduced.
[0094]
ReV is a value that changes depending on whether or not the preliminary light emission has been restarted. In the first preliminary light emission, the value is 0. However, when the photometric value is saturated in the first preliminary light emission, the value is set to −3 EV, the gain is reduced, and the second preliminary light emission is performed.
[0095]
Sa [i] is a correction value calculated according to the type of the photographing lens and the set aperture value. A correction value is obtained for each area (a calculation formula is determined in advance by an experiment or the like).
[0096]
Next, a gain DApre [i] to be actually set in the light control element 15 is calculated by the following (Equation 4).
[0097]
DApre [i] = (pre_level [i] −GaV [i] * pre_gamma) * T / Tref (i = 1 to 5) (Equation 4)
However, each variable indicates the following contents.
pre_level [i]: reference value of preliminary light emission dimming level
pre_gamma: gamma adjustment value
T: Current temperature
Tref: temperature at the time of adjustment
It should be noted that the reason why GaV [i] is negative is that the gain increases when the DA terminal voltage of the light control element 15 shown in FIG. 7 is reduced.
[0098]
In S506, a command for instructing monitor light emission (small) is transmitted (monitor light emission 1). Here, the light amount of the first monitor emission is determined in advance by a standard (for example, the guide number of ISO 100 is 2), so it is not necessary to specify the light amount on the SB side.
In step S507, the integration of the light control element 15 is started in synchronization with the monitor light emission of the SB, the timer is operated at the light emission time of the monitor light emission (small) read out in advance in the SB communication of step S203, and the integration is terminated. The data AD [i] (i = 1 to 5) is read (accumulation / read 1).
[0099]
In S508, it is determined whether or not the photometric data AD [i] (i = 1 to 5) can be used for calculation. Specifically, it is determined whether or not the maximum value (ADmax) of the AD [i] data in the five regions is equal to or higher than the usable level (AD1) and the maximum value (ADmax) does not exceed the saturation level (AD2). . In the case of a light control device having an output of 0 to 4 V, for example, AD1 = 0.5 V and AD2 = 3.7 V. If the data is usable, the process proceeds to S513 without performing the second monitor emission, and if the data is not usable, the process proceeds to S509.
[0100]
In S509, if ADmax <AD1 in the determination of S508, the next light emission amount is calculated by the following (Equation 5), and the gain setting of the light control element 15 is the same as S505.
[0101]
GN2 = GN1 + {2 * log2 (ADagc / ADmax)} (Equation 5)
However, each variable indicates the following contents.
GN2: Next light emission (unit: guide number)
GN1: Previous light emission (unit: guide number)
ADagc: Preliminary photometric value target level (unit: V or A / D value)
ADmax: maximum value of previous photometry value (unit: V or A / D value)
If ADmax> AD2, the gain is recalculated by substituting -3EV for ReV as described in (Equation 3) of S505, and the next light emission amount is the same as in S506. I do.
[0102]
In S510, the IC gain of the dimming element 15 determined in S509 is set (IC gain setting 2).
In step S511, a command for instructing monitor light emission and data for specifying light amount are transmitted based on the light emission amount obtained in step S509. The specific method is the same as in S308. In S512, the integration of the light control element 15 is started in synchronization with the SB monitor light emission, the timer is operated with the monitor light emission time read out in advance in the SB communication in S203 to complete the integration, and the photometric data AD [ i] (i = 1 to 5) is read (accumulation / readout 2).
In step S <b> 513, GV [i] (i = 1 to 5) is calculated from the preliminary photometry result using the above-described (Equation 2).
[0103]
FIG. 18 is a subroutine flowchart showing the control content of the preliminary light emission 4.
When S503 in FIG. 17 is executed, this subroutine is called and executed. This flowchart is applied to the old format, and corresponds to the time chart of FIG. 8 or FIG. Hereinafter, each step will be described.
[0104]
In S601, a gain DApre [i] to be set in the light control element 15 is calculated by the same method as in S505 (gain setting 1).
In S602, emptying is performed twice.
In S603, the timing of the trpe measurement starts. Start integration with IS = L.
In S604, 0 is set to a variable Qpre indicating a small number of times of preliminary light emission.
In S605, 1 is added to Qpre.
In S606, small light emission (chop light emission) is performed with the light emission amount GNp1.
[0105]
In S607, it is determined whether or not a stop signal has been output. If a stop signal has been output, the process proceeds to S690. If no stop signal has been output, the process proceeds to S608.
In S608, it is determined whether or not the number of small light emission has reached Qpre_max times set as the maximum value. If the number has reached, the process proceeds to S609, and if not, the process returns to S605.
[0106]
In S609, the tpre timing is ended.
In S610, the integral value IGpre [i] is read.
In S611, the integration time timer is set to tpre.
In S612, integration is performed for tpre with the same gain as in S603, and the integrated value IGtei [i] is read.
In step S <b> 613, GV [i] (i = 1 to 5) is calculated from the preliminary photometry result using the above-described (Equation 2).
[0107]
Here, the calculation of the main light emission amount will be described.
First, using GV [i] or GV [i, j] of each region obtained by preliminary light emission, the object reflectance ReSEV [i] or ReSEV [i, j] of each region is shown below ( It is calculated using equation (6). (However, hereinafter, [i, j] is omitted and represented by [i].)
ReSEV [i] = 2 * X + AV−GV [i] (i = 1 to 5) (Equation 6)
X: Shooting distance (unit: m)
AV: shooting aperture value (unit: AV)
Here, ReSEV [i] is a variable that is 0 when the reflectance is a standard value, +1 when the reflectance is +1 step higher than the standard, and −1 when the reflectance is -1 step.
[0108]
Next, using ReSEV [i], a weighting number RefG [i] for each region according to the reflectance is calculated using (Equation 7).
RefG [i] = 1 / (2 ＾ (Abs (RefG [i]))) (i = 1 to 5) (Expression 7)
Here, Abs () is a function for calculating the absolute value in (). RefG [i] is a variable which is 1 when the reflectance of the subject is a standard value as shown in FIG. 21 (a), and decreases with increasing distance from the standard value.
[0109]
Next, RefG [i] is normalized by (Equation 8), and a weight wt [i] for each region is calculated.
wt [i] = RefG [i] / Σ (RefG [i]) (i = 1 to 5) (Equation 8)
Here, Σ () is a function for calculating the sum of the variables RefG [i] (i = 1 to 5) in ().
[0110]
Next, by using the ReSEV [i] obtained by (Equation 6) again, the reflectance correction value RefMain for the entire object field is calculated by (Equation 9).
RefMain = log2 (Σ (wt [i] * 2 ＾ ReSEV [i])) (i = 1 to 5) (Equation 9)
Here, Σ () is a function similar to (Equation 8), and log2 is a function representing a logarithm of 2.
Using RefMain, the main light emission amount correction value deltaY is calculated by (Equation 10).
deltaY = krm * RefMain (Equation 10)
[0111]
FIG. 21B shows the relationship between the reflectance and deltaY. Here, krm is a constant for adjusting the degree of correction of the reflectance, and a numerical value of about krm = 0.5 is used. However, krm may be changed as needed.
[0112]
In the case of D-TTL control, the main light emission amount multiple Kgn is calculated by (Equation 11) and (Equation 12) using wt [i], deltaY, and the like. Here, the main light emission amount multiple Kgn corresponds to the calculation result of S112.
K = Σ (2 ＾ (GV [i]) * wt [i]) / (GNpre ＾ 2) (Equation 11)
However,
GV [i]: GV value of area used for calculation
w [i]: weight coefficient of area used for calculation
GNpre: Guide number for preliminary flash
For example, in the case of SE lock, GV [i] uses only GV [3, 3] and sets w [3, 3] = 1.
The main light emission amount multiple value Kgn is obtained as follows.
Kgn = 12 * (log2 (K)) + deltaY) +128 (Equation 12)
[0113]
In the case of real-time dimming control, the following SaV [i] and DAhon [i] are calculated using wt [i], deltaY, and the like. Here, the IC gain DAhon [i] of each area at the time of main light emission corresponds to the calculation result of S111.
First, SaV [i] of each area is calculated by (Equation 13).
SaV [i] = SV + log2 (Wt [i])-deltaY (Equation 13)
here,
SV: film sensitivity value (APEX value)
Wt [i]: weighting factor for each area
deltaY: light control correction value
[0114]
Next, the IC gain DAhon [i] of each area is calculated by (Equation 14).
DAhon [i] = (hon_level [i] −SaV [i] * hon_gamma) * T / Tref (i = 1 to 5) (Expression 14)
here,
hon_level [i]: reference value of dimming level
hon_gammma: gamma adjustment value
T: Current temperature
Tref: temperature at the time of adjustment
It should be noted that the reason why −SaV [i] is negative is that the gain increases when the DA terminal voltage of the light control element 15 shown in FIG. 7 is reduced.
[0115]
According to the present embodiment, a sensor for performing photometry of flash light can be selected from the photometric element 9 and the dimming element 15 as necessary. The operation in which the time interval between the preliminary light emission and the main light emission is inconspicuous can be performed according to the request or the like.
In addition, during the preliminary light emission of the new format, the amount of light of the second preliminary light emission is made variable in accordance with the result of the first preliminary light emission. Can be obtained.
[0116]
(Modified form)
Various modifications and changes are possible without being limited to the embodiment described above, and these are also within the equivalent scope of the present invention.
In the present embodiment, an electronic still camera using an imaging device such as a CCD has been described as an example. However, the present invention is not limited to this, and can be similarly applied to, for example, a camera that exposes a silver halide film.
[0117]
【The invention's effect】
As described above in detail, according to the present invention, the following effects can be obtained.
(1) Since a preliminary light metering selector is provided for selecting which of the first flash light meter and the second flash light meter is used for photometry of preliminary light emission, optimal preliminary light emission can be performed as necessary. .
[0118]
(2) The sensor of the first flash photometry unit also serves as the sensor of the constant light photometry unit that measures the brightness of the steady light, and the sensor of the second flash photometry unit reflects the subject of the main light emission during the main light emission. Since the sensor of the flash light control unit that performs light control by measuring light is also used, an existing sensor can be effectively used.
[0119]
(3) When the first flash metering section is selected by the preliminary metering selecting section, the preliminary flash is performed before the mirror-up, and when the second flash metering section is selected, the preliminary flash is performed after the mirror-up. Therefore, it is possible to perform control appropriate for the position where the flash photometry unit is arranged.
[0120]
(4) When the first preliminary light emission mode in which preliminary light emission is performed alone before photographing is executed, the first flash light meter is selected, and the second preliminary light emission and main light emission are continuously performed during photographing. When the preliminary light emission mode is executed, the second flash photometry unit is selected, so that both SE lock and real-time light control can be achieved.
[0121]
(5) The flash metering selector selects which of the first flash metering unit and the second flash metering unit performs photometry of preliminary flashing according to the mounted flash emitting unit. Even when the unit is mounted, the preliminary light emission can be performed correctly.
[0122]
(6) Regardless of whether the first flash photometer or the second flash photometer performs preflash photometry, a preliminary flash control unit that instructs the flash flash unit to perform preflash by the same control method is provided. Therefore, the system can be simplified.
[0123]
(7) The control method of the preliminary light emission performed by the preliminary light emission control unit is a method of performing the first preliminary light emission of a predetermined light amount and then performing the second preliminary light emission as necessary. Even in this case, the preliminary photometry can be reliably performed.
[0124]
(8) The flash light emitting unit performs a first preliminary light emission of a predetermined light amount, and then performs a second preliminary light emission with a variable light amount as necessary, and a flash light metering unit at the time of the first preliminary light emission. Since a preliminary light emission determination unit that determines the necessity of the second preliminary light emission according to the output is provided, it is possible to obtain an accurate preliminary light measurement value while minimizing the energy consumed for the preliminary light emission.
[0125]
(9) Since the preliminary light emission control unit calculates the light amount of the second preliminary light emission in accordance with the output of the flash photometry unit at the time of the first preliminary light emission, the light amount of the second preliminary light emission can be emitted with the optimal light amount. .
[0126]
(10) The preliminary light emission control unit communicates only information for instructing preliminary light emission when performing the first preliminary light emission, and transmits the information for instructing preliminary light emission and the light emission amount information when performing the second preliminary light emission. Since communication is performed, the operation can be performed at high speed without performing unnecessary communication.
[0127]
(11) The flash light emission unit generates a synchronization signal synchronized with the preliminary light emission, and the flash light measurement unit performs light measurement in synchronization with the synchronization signal, so that only necessary flash light can be measured.
[Brief description of the drawings]
FIG. 1 is a diagram showing an optical system according to an embodiment of the present invention.
FIG. 2 is a block diagram illustrating a configuration of a camera body 30, a lens body 40, and an SB body 50 according to the embodiment.
FIG. 3 is a diagram illustrating a photometry area of the photometry element 9;
FIG. 4 is a diagram for explaining the operation of the photometric element 9;
FIG. 5 is a diagram illustrating a focus detection unit 16;
FIG. 6 is a diagram showing an optical system of a flash photometry unit 33 and a divided shape of a photometry area.
FIG. 7 is a diagram illustrating a light control element 15.
FIG. 8 is a timing chart for easily explaining the basic operation of real-time TTL light control by preliminary light emission of an old format.
FIG. 9 is a timing chart for easily explaining a basic operation of TTL light control (hereinafter, referred to as D-TTL light control) of a GN control method by preliminary light emission of an old format.
FIG. 10 is a timing chart for easily explaining the basic operation of real-time TTL light control by preliminary light emission of a new format.
FIG. 11 is a timing chart for easily explaining the basic operation of D-TTL dimming by preliminary light emission of a new format.
FIG. 12 is a timing chart showing the basic operation of the preliminary light metering method using the light metering element 9 and performing the preliminary light emission in a new format.
FIG. 13 is a flowchart showing a program of the camera microcomputer 31.
FIG. 14 is a subroutine flowchart showing control contents of pre-shooting processing.
FIG. 15 is a subroutine flowchart showing control contents of preliminary light emission 1.
FIG. 16 is a subroutine flowchart showing control contents of preliminary light emission 2;
FIG. 17 is a subroutine flowchart showing control contents of preliminary light emission 3;
FIG. 18 is a subroutine flowchart showing control contents of preliminary light emission 4;
FIG. 19 is a diagram illustrating various parameters of the flash control device according to the present embodiment.
FIG. 20 is a diagram showing a relationship between BvV [i] and BV [i].
FIG. 21 is a diagram illustrating RefG [i] and deltaY.
FIG. 22 is a diagram illustrating a conventional technique.
FIG. 23 is a diagram illustrating a conventional technique.
[Explanation of symbols]
1 Shooting lens
2 Main mirror
3 Diffusion screen
4 Condenser lens
5 Penta prism
6 Eyepieces
7 Prism for photometry
8 Photometric lens
9 Photometric element
10 aperture
11 Shutter
12 Image sensor
13 Submirror
14 Dimming lens
15 Dimming element
16 Focus detector
17 Flash emitting part
18 Light emission monitor
30 Camera body
31 Camera microcomputer
32 Ambient light meter
33 Flash meter
34 Lens drive unit
35 Aperture control unit
36 Sensitivity setting section
37 Release switch
38 Custom setting section
40 Shooting lens body
41 Lens microcomputer
42 Distance encoder
50 SB body
51 SB microcomputer

Claims (11)

A flash control device that controls a flash light emitting unit that performs preliminary light emission and main light emission,
A first flash metering section for measuring the subject reflected light of the preliminary light emission by the flash light emitting section; A flash photometer,
A preliminary light metering selection unit that selects which of the first flash metering unit and the second flash metering unit performs photometry of preliminary light emission;
A flash control device comprising: The flash control device according to claim 1,
The sensor of the first flash photometry unit also serves as a sensor of the constant light photometry unit that measures the brightness of the steady light,
The sensor of the second flash light metering section also serves as a sensor of a flash light metering section that performs light control by measuring the subject reflected light of the main light emission during the main light emission,
A flash control device. The flash control device according to claim 1 or 2,
The device including the flash control device is a camera with a quick return mirror,
When the first flash photometry unit is selected by the preliminary photometry selection unit, preliminary flash is performed before mirror up,
When the second flash photometer is selected, performing preliminary light emission after mirror up;
A flash control device. The flash control device according to any one of claims 1 to 3,
A first preliminary light emission mode in which preliminary light emission is performed independently before photographing;
A second preliminary light emission mode in which preliminary light emission and main light emission are continuously performed during shooting,
With
When the first preliminary light emission mode is executed, the preliminary light measurement selection unit selects the first flash light measurement unit,
When the second preliminary light emission mode is executed, selecting the second flash photometer;
A flash control device. The flash control device according to any one of claims 1 to 4,
The flash light emitting unit is detachable from equipment including a flash control device,
The preliminary light metering selector selects which of the first flash light meter and the second flash light meter performs pre-light metering in accordance with the mounted flash light emitter,
A flash control device. The flash control device according to any one of claims 1 to 5,
Regardless of whether the first flash photometer or the second flash photometer performs preflash photometry, a preliminary flash control unit that instructs the flash flash unit to perform preflash by the same control method is provided. Was it,
A flash control device. The flash control device according to claim 6,
The control method of the preliminary light emission performed by the preliminary light emission control unit includes:
A method of causing the flash light emitting section to perform a first preliminary light emission of a predetermined light amount and then perform a second preliminary light emission as necessary;
A flash control device. A flash control device that controls a flash light emitting unit that performs preliminary light emission and main light emission,
A flash photometric unit for measuring the subject reflected light of the preliminary light emission,
A preliminary light emission control unit that causes the flash light emission unit to perform a second preliminary light emission with a variable light amount as necessary after the first preliminary light emission of a predetermined light amount;
A preliminary light emission determination unit that determines the necessity of the second preliminary light emission in accordance with an output of the flash light meter during the first preliminary light emission;
A flash control device comprising: The flash control device according to claim 8,
The preliminary light emission control unit calculates a light amount of the second preliminary light emission in accordance with an output of the flash photometry unit at the time of the first preliminary light emission;
A flash control device. The flash control device according to claim 8 or 9,
The preliminary light emission control unit communicates only information for instructing preliminary light emission when performing the first preliminary light emission, and communicates information for instructing preliminary light emission and light emission amount information when performing the second preliminary light emission. Having a communication unit,
A flash control device. The flash control device according to any one of claims 8 to 10,
The flash light emitting unit is detachable from equipment including a flash control device,
The flash light emitting unit generates a synchronization signal synchronized with the preliminary light emission,
The flash photometric unit performs photometry in synchronization with the synchronization signal,
A flash control device.

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