Modify AutoISO Max with CHDK or SDM uBasic command

Jim

32

« on: 19 / April / 2010, 11:33:40 »

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I am looking to modify the upper end of the AutoISO setting. Example my A570IS and G9 both have the standard Auto ISO that runs from 80-200. I would like to change this to Auto ISO 80-1600.

Special use: I take picture from kites and need to shoot high shutter speeds (to reduce image blur). I typically fly with the shutter speed fixed (in the range of 1/500+) using the standard Tv mode. During long flights as the sun sets...the AutoISO 80-200 range falls short of what is needed for usable image....AutoISO 80-1600 would be great (yes - more noise, but better than black screen).

Shooting in the Tv mode (fixed shutter speed) disables the Hi ISO mode :-( otherwise just setting the ISO to high would do the trick.

I searched the forum and came across this post: http://chdk.setepontos.com/index.php/topic,638.msg18015.html#msg18015
which looks close to my requirement, not fully familiar with the "CONFIG_INFO" script syntax or limitations.

I figure there has to be an easy way to do this with either a CHDK or SDM command.

Any help?

Jim (WW)

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an0n

152

Re: Modify AutoISO Max with CHDK or SDM uBasic command

« Reply #1 on: 19 / April / 2010, 12:39:34 »

Hi Jim,

Pages 12 and 13 of the User Guide has Custom Auto ISO, perhaps that will help.

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A720IS.

Microfunguy

4037

Re: Modify AutoISO Max with CHDK or SDM uBasic command

« Reply #2 on: 19 / April / 2010, 12:41:27 »

Looking at the CHDK code, the setting of auto ISO is not enabled for Tv, Manual or stitching modes.

Otherwise, in the menu you can set an auto ISO value of 800 maximum.

I have not followed the development of this feature, maybe there is a good reason for not working in Tv mode.

Reyalp will probably know.

If you can research it, maybe we can take it further.

David

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