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Old Aug 21, 2009, 9:28 AM   #1
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Default Surprised by tv when shooting AV priority

Both of these photos were shot at an ISO of 400 within moments of one another.

The original purpose was to compare the impact of an AV setting of 2.8 vs 13.

What surprised me what the way the camera compensated for these extreme settings by altering the shutter speed.

The av of 13 had a shutter speed of 1/250
The av of 2.8 had a shutter speed of 1/5000 (that's not a typo).

Still being a novice photographer, I was really surprised by that huge difference.
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Old Aug 21, 2009, 9:53 AM   #2
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Hi FP,

Yes it is right. You have a huge variance in the amount of light getting into the camera.

Here is a quick table starting at the f2.8 setting, each step is a stop or halving of light, so halving of shutter speed to get the same exposure.

f2.8----1/5000
f4.0----1/2500
f5.6----1/1250
f8.0---- 1/640
f11----1/320
f16----1/160

So your f13 fall exactly where expected at 1/250.

Simple
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Old Aug 21, 2009, 11:19 AM   #3
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Quote:
Originally Posted by Mark1616 View Post
Hi FP,

Yes it is right. You have a huge variance in the amount of light getting into the camera.

Here is a quick table starting at the f2.8 setting, each step is a stop or halving of light, so halving of shutter speed to get the same exposure.

f2.8----1/5000
f4.0----1/2500
f5.6----1/1250
f8.0---- 1/640
f11----1/320
f16----1/160

So your f13 fall exactly where expected at 1/250.

Simple
And opening the aperture 1 stop, for example from f4 to f2.8, doubles the exposure. The same change in exposure is applied to changes in shutter speed. 1/500 sec is half the exposure of 1/250 and 1/250 sec is double the exposure value of 1/500 sec.
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