f2.8 and f7.1 - Script Writing - CHDK Forum

f2.8 and f7.1

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f2.8 and f7.1
« on: 30 / January / 2009, 15:16:55 »
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hi evrebody...i'm using chdk script for 5 months and it really helped me to improve my photos.


i have one question...i couldnt find solution.

when i press half shutter button i can see on my display shutter speed and how much it is open...if it is good light than is f7.1 and if is bad its f2.8 or smillar.

my question is can i controll this so that i can put f5.5 or f10 or something...

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Offline Hacki

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Re: f2.8 and f7.1
« Reply #1 on: 30 / January / 2009, 15:20:14 »
It would have helped if you wrote which camera model you have, but here's my best guess:

Your camera does not have an iris diaphragm. Older models like from the powershot A4** line or the IXUS / Powershot SD* series do not have iris diaphragms, they have a ND filter instead. That means the size of the aperture is fixed, the camera controls the amout of light by either swinging in or out the ND filter. Hence the fixed 2.8 or 7.1.

Re: f2.8 and f7.1
« Reply #2 on: 30 / January / 2009, 15:28:51 »
canon a550

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Offline Hacki

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Re: f2.8 and f7.1
« Reply #3 on: 30 / January / 2009, 15:30:57 »
Indeed, the A550 does not have an iris diaphragm.


Re: f2.8 and f7.1
« Reply #4 on: 30 / January / 2009, 15:34:21 »
i thought so :) tnx anyway

 

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