SD1000 ISO Settings Error - page 4 - AllBest's Builds - CHDK Forum

SD1000 ISO Settings Error

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Re: SD1000 ISO Settings Error
« Reply #30 on: 18 / March / 2008, 04:37:21 »
Right. If I were to set the ISO manually by original camera firmware, it would result in the same thing. Camera would know ISO before shoot.
:blink: You set ISO after exposure? Isn't exposure based on ISO? Shouldn't you set ISO then compute? Very confused....
Unfortunately CHDK is only HACK tool. We investigate abilities of camera and we can do only that we can do at present moment.
May be later CHDK will be know how to do it in another way. And you can help CHDK in it ;-)

Hmm... You can't set Propcase from CHDK? That is, when I select ISO override in menu, just change the ISO_Mode prop case. This should be possible. How does the script engine do it?  :blink: Doesn't CHDK run the script engine? So, CHDK should be able to do everything script engine does.
Override engine and script are principally different. Setting of property case that you want in limits of override engine doesn't give us desirable results (It have been tested)
I can confirm that ISO3200 via propcase #149 works perfectly. Right white balance, etc. ISO6400 has green hue, but works. I get a overall brighter picture with faster shutter speeds. Any other values between 6400 and 1600 has purple hue.
faster shutter speeds is due to the fact that CHDK deceive camera firmware here. It is not correct set of exposure parameters. I'm sure in it
My deep testing of NATIVE ISO modes of a650 have showed that even NATIVE ISO modes of 1600 and 3200 of above-mentioned camera are ONLY gamma-correction of shots with smaller "real" ISOs......
You can use my or your scripts to do shots with different ISO values but NECESSARILY with FIXED av and tv values. After that for clear testing you need to use dcraw with this set of parameters: "dcraw.exe -4 -v -a %1" (or "dcraw.exe -4 -v -w %1") where  %1 - is your raw file name. Next you need to compare brightness of images. And after that you can do some conclusions......... It will be fair experiment
9mb RAW files are a pain, I can post JPG's on this forum if it would help.
Thanks for the help Allbest.
It is a pity.  Community can't see you results and can't do the same conclusions as you have do...
Thanks! :)


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