What’s The Difference?

During the Introduction To Photography Workshop, in order to practice  thinking about photographic composition, we talk about equivalent  exposures.

What’s the difference between: 1/30 @f-22, 1/250 @ f-8 , and 1/2000 @ f-2.8 ?

In terms of exposure  ABSOLUTELY  NOTHING! ; In terms of composition, and our ability to create the photograph, EVERYTHING !

Each of these f-stop and shutter  speed  combination’s  is an equivalent exposure. In other words, when it  comes to the  amount of light entering our cameras; 1/30 @f-22 = 1/250 @ f-8  = 1/2000 @ f-2.8.

Assuming the focal length of  the lens is the same and the distance  we are focused  on is the same here are  the visual variances that we can expect and the limitations that we face.

• At 1/30 @ f-22 we’ll have a deep depth of field, and anything that’s moving fairly quickly will probably record  as a  blur. If the focal length of our  lens is longer than 28 mm, we’ll probably need  a tripod or  something to rest our camera  on to avoid the blur  that would be caused by hand holding our  camera during  the exposure.
• At 1/250 @ f-8 we’ll  have a moderate depth of field, and anything that’s moving fairly quickly will probably record as stopped motion. As long as the focal length of our lens is, shorter than 300 mm we could get away  with hand holding our camera,  otherwise we’ll probably need  a tripod or  something to rest our camera  on to avoid the blur  that would be caused by hand holding our  camera during the exposure.
• At 1/2000 @ f-2.8 we’ll  have a very shallow depth of field, and almost anything that’s moving  will probably record as stopped motion. As long as the focal length of our lens is, shorter than 2000 mm (I don’t know if  they  even make 2000 mm lenses) we could get away  with hand holding our camera,  otherwise we’ll probably need  a tripod or  something to rest our camera  on to avoid the blur  that would be caused by hand holding our  camera during the exposure.  As long as the focal length of our lens is, shorter than  2000 mm we could get away  with hand holding our camera,  otherwise we’ll probably need  a tripod or  something to rest our camera  on to avoid the blur  that would be caused by hand holding our  camera during the exposure.

This entry was posted on Friday, December 12th, 2008 at 8:59 pm. It is filed under Learn Photography. You can follow any responses to this entry through the RSS 2.0 feed.