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Taking exposure readings
Correct exposure is a relative term . Under normal lighting conditions , film will record an image over a wide range of exposures ; which exposure you choose depends to a great extent on how you want your subject to look . Generally you will want the subject to record with detail throughout , but some- times you may want to emphasize one part by selectively measuring the exposure .
An image formed through the lens will cover a range of brightness , depending on the tones of the subject and the lighting . If a subject is harshly lit , it will have a wider range from deep shadow to bright high- light than if it is flatly lit , as in overcast daylight . Ideally you will want important detail from both light and dark areas to record . However , film cannot record a vast range of brightness all in the same picture . If you try to expose long enough for the deep shadows , the lightest parts of the picture may be overexposed and vice versa .
Exposure tables are useful guides for " average " subjects in specified lighting con- ditions , but an exposure meter is much more versatile and accurate because it reads your particular subject and lighting conditions . For a subject like the picture right , a general overall meter measurement will give good results . But sometimes the meter can give a misleading reading of the exposure . Some of the ways to avoid this are explained below and on the opposite page .
Using one overall reading :
The exposure for the sort of scene above can be accurately judged by taking one general meter read- ing from the camera position . Shadows and highlights in the subject are about equal in area and the meter will average them both . The meter must point at the same area of the scene as you have in your viewfinder .
Where general readings are deceptive :
A general reading is misleading if the important element is quite small . When the background is bright , below left , the reading underexposes the face so that on the print it is too dark .
A dark background , bottom left , produces the opposite effect the face is now too pale ( over- exposed ) . In the two larger prints . below , the light readings were taken for the figure alone , so that the background lighting does not dominate the result .
Taking a selective reading :
To overcome the type of exposure reading difficulties described left , you must make sure that the meter only reads from the most important area of the subject - in this case the subject's face .
Moving closer
For built - in meters that give a general reading , move in until the main subject fills the viewfinder . You can then take your exposure reading without the background affecting the reading . Move back again to take the photograph .
Taking a spot reading
If your camera has a through - the- lens meter which makes a " spot " reading ( see p . 40 ) , align this marked area of the focusing screen with the main subject . Since the meter ignores other parts of the picture , it will give the correct exposure for the main subject .
Local hand meter reading
If you use a hand - held meter you can bring it up close to the main subject to take your reading . In doing so , be careful not to cast a shadow on the area being measured .
Exposing to suit the subject :
The exact exposure you give de- pends upon which parts of the picture you have selected as being important . In the near right pic- ture the exposure ( 1/60 sec at f11 ) was read mostly from the shadow area , so that the highlights are very overexposed , with a con- sequent loss of detail . The center picture was given an average overall reading ( 1/250 sec at f11 ) . For the third version , far right . the exposure ( 1/500 sec at f16 ) was read from the highlights . The picture is underexposed , but is perhaps the most satisfying result .
Brightness range reading :
Sometimes you want to record as much detail as possible in a sub- ject that has a wide brightness range ( high contrast ) like the photograph , right . If you have . time , use your built - in meter to take two readings . For example , taking a reading from the darkest part of the subject may suggest an aperture of 12-8 : then reading from the lightest part may give you fl11 ( at the same shutter speed halving the difference between these two settings you will arrive at f5-6 as the best compromise setting .
Substitute readings :
Often action pictures allow you no time to make several elaborate readings . Also , on some occa- sions , you may not want to make it obvious that you are taking pictures . One method of solving this is to take a reading from a substitute that is about midway in tone between the darkest and lightest parts of your subject . This could be a mid - gray card , or your hand ( as a substitute for someone's face , for example ) . The action pic- ture below is typical of the sort of subject that can only be taken if the exposure is pre - set from a substitute reading .
Reminders : Film and exposure
Film sensitivity is given by its speed
Film sensitivity is given in ASA numbers , where double the number means double the speed . Fastest film gives coarsest grain .
Exposure is related to subject brightness and film speed
To measure exposure , subject brightness ( surface tones and lighting ) must be related to the speed of the film .
Light meters are sometimes coupled to camera controls and differ in the area they read
Exposure meters are more versatile than exposure tables . Most meters are built into the camera , often coupled to its controls " automatic " metering is based on either shutter or aperture priority .
Built - in meters differ in the subject area they read . Those that take general readings suit evenly distributed tones ; spot systems are best for measuring one key area or checking brightness range ; a center - weighted meter is good for most general subjects .
Take the readings from the most important subject area
Try to take your reading from the most important subject area . If you want to record extremes of brightness , work out an average exposure .
Taking exposure readings
Correct exposure is a relative term . Under normal lighting conditions , film will record an image over a wide range of exposures ; which exposure you choose depends to a great extent on how you want your subject to look . Generally you will want the subject to record with detail throughout , but some- times you may want to emphasize one part by selectively measuring the exposure .
An image formed through the lens will cover a range of brightness , depending on the tones of the subject and the lighting . If a subject is harshly lit , it will have a wider range from deep shadow to bright high- light than if it is flatly lit , as in overcast daylight . Ideally you will want important detail from both light and dark areas to record . However , film cannot record a vast range of brightness all in the same picture . If you try to expose long enough for the deep shadows , the lightest parts of the picture may be overexposed and vice versa .
Exposure tables are useful guides for " average " subjects in specified lighting con- ditions , but an exposure meter is much more versatile and accurate because it reads your particular subject and lighting conditions . For a subject like the picture right , a general overall meter measurement will give good results . But sometimes the meter can give a misleading reading of the exposure . Some of the ways to avoid this are explained below and on the opposite page .
Using one overall reading :
The exposure for the sort of scene above can be accurately judged by taking one general meter read- ing from the camera position . Shadows and highlights in the subject are about equal in area and the meter will average them both . The meter must point at the same area of the scene as you have in your viewfinder .
Where general readings are deceptive :
A general reading is misleading if the important element is quite small . When the background is bright , below left , the reading underexposes the face so that on the print it is too dark .
A dark background , bottom left , produces the opposite effect the face is now too pale ( over- exposed ) . In the two larger prints . below , the light readings were taken for the figure alone , so that the background lighting does not dominate the result .
Taking a selective reading :
To overcome the type of exposure reading difficulties described left , you must make sure that the meter only reads from the most important area of the subject - in this case the subject's face .
Moving closer
For built - in meters that give a general reading , move in until the main subject fills the viewfinder . You can then take your exposure reading without the background affecting the reading . Move back again to take the photograph .
Taking a spot reading
If your camera has a through - the- lens meter which makes a " spot " reading ( see p . 40 ) , align this marked area of the focusing screen with the main subject . Since the meter ignores other parts of the picture , it will give the correct exposure for the main subject .
Local hand meter reading
If you use a hand - held meter you can bring it up close to the main subject to take your reading . In doing so , be careful not to cast a shadow on the area being measured .
Exposing to suit the subject :
The exact exposure you give de- pends upon which parts of the picture you have selected as being important . In the near right pic- ture the exposure ( 1/60 sec at f11 ) was read mostly from the shadow area , so that the highlights are very overexposed , with a con- sequent loss of detail . The center picture was given an average overall reading ( 1/250 sec at f11 ) . For the third version , far right . the exposure ( 1/500 sec at f16 ) was read from the highlights . The picture is underexposed , but is perhaps the most satisfying result .
Brightness range reading :
Sometimes you want to record as much detail as possible in a sub- ject that has a wide brightness range ( high contrast ) like the photograph , right . If you have . time , use your built - in meter to take two readings . For example , taking a reading from the darkest part of the subject may suggest an aperture of 12-8 : then reading from the lightest part may give you fl11 ( at the same shutter speed halving the difference between these two settings you will arrive at f5-6 as the best compromise setting .
Substitute readings :
Often action pictures allow you no time to make several elaborate readings . Also , on some occa- sions , you may not want to make it obvious that you are taking pictures . One method of solving this is to take a reading from a substitute that is about midway in tone between the darkest and lightest parts of your subject . This could be a mid - gray card , or your hand ( as a substitute for someone's face , for example ) . The action pic- ture below is typical of the sort of subject that can only be taken if the exposure is pre - set from a substitute reading .
Reminders : Film and exposure
Film sensitivity is given by its speed
Film sensitivity is given in ASA numbers , where double the number means double the speed . Fastest film gives coarsest grain .
Exposure is related to subject brightness and film speed
To measure exposure , subject brightness ( surface tones and lighting ) must be related to the speed of the film .
Light meters are sometimes coupled to camera controls and differ in the area they read
Exposure meters are more versatile than exposure tables . Most meters are built into the camera , often coupled to its controls " automatic " metering is based on either shutter or aperture priority .
Built - in meters differ in the subject area they read . Those that take general readings suit evenly distributed tones ; spot systems are best for measuring one key area or checking brightness range ; a center - weighted meter is good for most general subjects .
Take the readings from the most important subject area
Try to take your reading from the most important subject area . If you want to record extremes of brightness , work out an average exposure .
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