Why CHDK always show INF for my DOF DISPLAY?

Jerrycai

« on: 03 / May / 2009, 05:39:01 »

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Hi everyone, I'm new guy of CHDK and taking photo.
I installed CHDK for my SX110. Everything looks like OK but DOF(depth of field).
When I take the photo like this:
F4.3 60mm(6-60mm) 1/100 ISO200
CHDK showed:
NL: INF
FL: INF
DOF: INF

I cannot understand why DOF showed INF here. Actually I think is should be a quite small value, cause I used long focus and big aperture.

Any reply on this issue is preferred. Thanks!

« Last Edit: 03 / May / 2009, 05:40:43 by Jerrycai »

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Microfunguy

4037

Re: Why CHDK always show INF for my DOF DISPLAY?

« Reply #1 on: 03 / May / 2009, 05:54:10 »

Quote from: Jerrycai on 03 / May / 2009, 05:39:01

I cannot understand why DOF showed INF here.

DOF is calculated from aperture and subject distance.

Does subject-distance value change when you half-press the shutter to autofocus ?

David

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PhyrePhoX

2254
make RAW not WAR

Re: Why CHDK always show INF for my DOF DISPLAY?

« Reply #2 on: 03 / May / 2009, 10:52:34 »

there is a long known bug in the dof calculator, more about it here.

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Jerrycai

Re: Why CHDK always show INF for my DOF DISPLAY?

« Reply #3 on: 04 / May / 2009, 10:09:45 »

Quote from: Microfunguy on 03 / May / 2009, 05:54:10

Quote from: Jerrycai on 03 / May / 2009, 05:39:01
I cannot understand why DOF showed INF here.

DOF is calculated from aperture and subject distance.

Does subject-distance value change when you half-press the shutter to autofocus ?

David

yes, the SD value changed (but display INF when more than 50m)

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