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CHOOSING THE EXPOSURE
One of the most important , and basic , skills in photography is controlling the quantity of light that reaches the film . In particular , it is essential to be able to record exactly the right level of light to achieve the effect you want . This is the basis of choosing an exposure setting : converting one particular brightness level ( in the scene ) into a certain range of tones in the photograph .
Nearly all modern cameras have built - in through - the - lens exposure meters , some of them quite sophisticated in the way they analyse the light . Also , the trend towards automation continues and increasingly camera meters measure the light and select the exposure controls without any need for the photo- grapher to become closely involved . Nevertheless , setting the exposure is not entirely a mechanical process - or at least , should not be . The idea of ' correct ' exposure applies only to recording as many of the tones of the scene as possible , and not to any aesthetic quality . Having full control over the image means exercizing judgement . This in turn means being able to override whatever meter you use . It is not good practice to rely so completely on an automatic meter that you lose touch with the practicalities of exposure .
Exposure meters , of whatever kind , measure the quantity of light , and then indicate an exposure setting that will reproduce this as an average tone . Most meters average all the tones in the scene to a common value . In a typical through - the - lens meter , the top of the frame is almost ignored , because in an outdoor setting , most people compose the view to include some sky at the top . This is known as ' weighting ' the meter pattern .
In a normal scene , this way of judging the exposure setting works well most of the time , but there are likely to be problems if the distribution of tones is in any way out of the ordinary . For instance , a small bright object against a dark background will turn out to be overexposed with this method , and a large bright background , such as with a backlit portrait , will over - influence the meter to cause under - exposure . An averaging meter gives every scene the same treat- ment : in black - and - white photography it shows the settings needed to produce a mid - grey , whether the subject is grey , black or white . Ultimately , therefore , you must judge the scene for yourself , and decide how much darker or lighter than an average grey you want it to appear in the photograph .
Fortunately most film in most situations will accept a margin of error . This is called exposure latitude , and black - and - white films have more latitude than colour . To an extent , unsatisfactory exposure can be corrected during printing , by using a different paper grade and altering the enlarger exposure . Neverthe- less , you should always be within one stop of an accurate exposure .
LEFT If there is a suspicion that your camera's built - in exposure meter may be fooled by a scene , and no hand - held meter is available , resort to bracketing . This technique involves taking one shot at the meter's suggested exposure , then two or three on either side of the meter's ideal . In this case , the photographer has shot the ideal ( opposite , top ) , then two more frames have then been shot , increasing the exposure by a half - stop for each . The process has finally been repeated , only this time the photographer has under- exposed .
RIGHT Although black and white negative film is far more tolerant of over - and under - exposure than colour slide film , it is still vital that you aim for the most accurate exposure possible . Compare the ideally exposed picture in this series with those both under - and over - exposed around it .
CHOOSING THE EXPOSURE
One of the most important , and basic , skills in photography is controlling the quantity of light that reaches the film . In particular , it is essential to be able to record exactly the right level of light to achieve the effect you want . This is the basis of choosing an exposure setting : converting one particular brightness level ( in the scene ) into a certain range of tones in the photograph .
Nearly all modern cameras have built - in through - the - lens exposure meters , some of them quite sophisticated in the way they analyse the light . Also , the trend towards automation continues and increasingly camera meters measure the light and select the exposure controls without any need for the photo- grapher to become closely involved . Nevertheless , setting the exposure is not entirely a mechanical process - or at least , should not be . The idea of ' correct ' exposure applies only to recording as many of the tones of the scene as possible , and not to any aesthetic quality . Having full control over the image means exercizing judgement . This in turn means being able to override whatever meter you use . It is not good practice to rely so completely on an automatic meter that you lose touch with the practicalities of exposure .
Exposure meters , of whatever kind , measure the quantity of light , and then indicate an exposure setting that will reproduce this as an average tone . Most meters average all the tones in the scene to a common value . In a typical through - the - lens meter , the top of the frame is almost ignored , because in an outdoor setting , most people compose the view to include some sky at the top . This is known as ' weighting ' the meter pattern .
In a normal scene , this way of judging the exposure setting works well most of the time , but there are likely to be problems if the distribution of tones is in any way out of the ordinary . For instance , a small bright object against a dark background will turn out to be overexposed with this method , and a large bright background , such as with a backlit portrait , will over - influence the meter to cause under - exposure . An averaging meter gives every scene the same treat- ment : in black - and - white photography it shows the settings needed to produce a mid - grey , whether the subject is grey , black or white . Ultimately , therefore , you must judge the scene for yourself , and decide how much darker or lighter than an average grey you want it to appear in the photograph .
Fortunately most film in most situations will accept a margin of error . This is called exposure latitude , and black - and - white films have more latitude than colour . To an extent , unsatisfactory exposure can be corrected during printing , by using a different paper grade and altering the enlarger exposure . Neverthe- less , you should always be within one stop of an accurate exposure .
LEFT If there is a suspicion that your camera's built - in exposure meter may be fooled by a scene , and no hand - held meter is available , resort to bracketing . This technique involves taking one shot at the meter's suggested exposure , then two or three on either side of the meter's ideal . In this case , the photographer has shot the ideal ( opposite , top ) , then two more frames have then been shot , increasing the exposure by a half - stop for each . The process has finally been repeated , only this time the photographer has under- exposed .
RIGHT Although black and white negative film is far more tolerant of over - and under - exposure than colour slide film , it is still vital that you aim for the most accurate exposure possible . Compare the ideally exposed picture in this series with those both under - and over - exposed around it .
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