Difference between revisions of "Exposure"

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'''Exposure''' is affected by adjustable three elements:
 
'''Exposure''' is affected by adjustable three elements:
−
* shutter speed
+
* '''shutter speed'''
−
* aperture
+
* '''aperture'''
−
* film/sensor speed (ISO). These three elements in combination add up to the amount of light that enters a camera to create a single photograph. For a multiple exposure where a single frame is exposed more than once the '''total exposure''' is the combination of all the exposures for that frame.
+
* '''film/sensor speed (ISO)'''
  
−
There is no single correct exposure for a specific photograph. At ISO 100 a picture taken at f22 at 1/4 seconds allows the same amount of light to hit the film or sensor as a picture taken at f2.8 at 1/250 second. Of course, not many people can hand hold a camera at 1/4 of a second and get a sharp image and you don't have much depth of field at f2.8, therefore, every exposure is a compromise. The photographer must decide how much depth of field they need while also thinking about how much of the action they want to freeze (or blur), what focal length lens they are using, can they use some sort of support, etc.  
+
These three elements in combination determine the amount of light that enters a camera to create an image. For a multiple exposure, where a single frame is exposed more than once, the '''total exposure''' is the sum of all the exposures for that frame.
 +
 
 +
There is no single correct exposure for a specific photograph. At ISO 100, a picture taken at f/22 at 1/4 seconds allows the same amount of light to hit the film or sensor as a picture taken at f/2.8 at 1/250 second. Of course, not many people can hand hold a camera at 1/4 of a second and get a sharp image and you don't have much depth of field at f/2.8; therefore, every exposure is a compromise. The photographer must decide how much depth of field they need, while also thinking about how much of the action they want to freeze (or blur), what focal length lens they are using, can they use some sort of support, etc.
 +
 
 +
To summarize these aspects of exposure:
 +
* '''Camera suppport:''' the longer the exposure (the slower the shutter speed), the greater the chance of blurring due to camera shake. Unless the camera is attached to a sturdy tripod, a higher shutter speed should be used.
 +
* The same is true if one is trying to photograph '''fast action'''.
 +
* The same is true when using '''long lenses:''' the longer the lens, the higher the shutter speed should be.
 +
* '''[[Depth of field]]:''' to increase depth of field (to get parts of the scene at greater distances in focus), a smaller [[aperture]] (higher [[f-stop]] number) should be used.
 +
* To decrease depth of field (focus only on subject and let everything else go out of focus), a large aperture (lower f-stop number) should be used.
  
 
== Exposure Bracketing & Compensation ==
 
== Exposure Bracketing & Compensation ==
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* [http://www.fredparker.com/ultexp1.htm THE ULTIMATE EXPOSURE COMPUTER]: Great articles on exposure geared towards nature photographers but useful for any kind of photographer.
 
* [http://www.fredparker.com/ultexp1.htm THE ULTIMATE EXPOSURE COMPUTER]: Great articles on exposure geared towards nature photographers but useful for any kind of photographer.
 
* [http://en.wikipedia.org/wiki/Exposure_%28photography%29 Wikipedia]
 
* [http://en.wikipedia.org/wiki/Exposure_%28photography%29 Wikipedia]
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{{stub}}
 
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{{glossary}}
 
{{glossary}}

Revision as of 11:15, 27 February 2006

Exposure is affected by adjustable three elements:

  • shutter speed
  • aperture
  • film/sensor speed (ISO)

These three elements in combination determine the amount of light that enters a camera to create an image. For a multiple exposure, where a single frame is exposed more than once, the total exposure is the sum of all the exposures for that frame.

There is no single correct exposure for a specific photograph. At ISO 100, a picture taken at f/22 at 1/4 seconds allows the same amount of light to hit the film or sensor as a picture taken at f/2.8 at 1/250 second. Of course, not many people can hand hold a camera at 1/4 of a second and get a sharp image and you don't have much depth of field at f/2.8; therefore, every exposure is a compromise. The photographer must decide how much depth of field they need, while also thinking about how much of the action they want to freeze (or blur), what focal length lens they are using, can they use some sort of support, etc.

To summarize these aspects of exposure:

  • Camera suppport: the longer the exposure (the slower the shutter speed), the greater the chance of blurring due to camera shake. Unless the camera is attached to a sturdy tripod, a higher shutter speed should be used.
  • The same is true if one is trying to photograph fast action.
  • The same is true when using long lenses: the longer the lens, the higher the shutter speed should be.
  • Depth of field: to increase depth of field (to get parts of the scene at greater distances in focus), a smaller aperture (higher f-stop number) should be used.
  • To decrease depth of field (focus only on subject and let everything else go out of focus), a large aperture (lower f-stop number) should be used.

Exposure Bracketing & Compensation

  • You light meter wants to make everything gray - how to adjust for this based on your subject and lighting.
  • over and under exposure - why would you deliberately want to over or under expose a shot.

Exposure Modes

Links

Glossary Terms
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