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does chdk specifically work in s90's low light mode?

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does chdk specifically work in s90's low light mode?
« on: 01 / July / 2010, 03:36:43 »
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been doing some testing after having the chdk set up. i primarily will be using the low light mode for its speed for everything, and the main reason i run the chdk is for the ability to control the iso...

in short, it seems the camera will still override whatever chdk settings i have in low light mode...

is that right? thanks.

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Offline reyalp

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Re: does chdk specifically work in s90's low light mode?
« Reply #1 on: 01 / July / 2010, 12:38:58 »
Do you have overrides working in regular (not-low light) mode ? If you do, and the same settings don't work in low light mode, then it's probably a bug. If not, it's probably user error ;)
Don't forget what the H stands for.

Re: does chdk specifically work in s90's low light mode?
« Reply #2 on: 01 / July / 2010, 15:24:04 »
reyalp,

thanks for the suggestion. actually, not really. here's what i found out after hours of fiddling around with it past midnight last night...

i realized (in low light mode) when i half press the shutter, i see the iso values on the lower right corner of the lcd do something curious: upon the half-press, it shows the override value i have set in shdk. and then it reverts to the iso value the camera assigns as it refocuses or whatever. that gave me an idea - i go into the menu portion, and thought maybe i can disable that - so i tried disabling servo af.

FINALLY! it is now working! on the half press, i see my override iso value, and stays that way as i take the picture. i am absolutely beside myself...(i also downloaded the chdk for my trusty ol' sd750 to tinker with...)

one curious question though. suppose i set shutter speed override to 1/30. it comes out as 1/30 on the shot details. BUT on the iso, it's a little 'off.' if i set it to 50, the shot is taken at 80. at 100, it takes the shot at 160. it's exactly 60% more. why is that?

speaking of bugs, did i read correctly that the s90 chdk ONLY has beta versions?

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Offline reyalp

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Re: does chdk specifically work in s90's low light mode?
« Reply #3 on: 01 / July / 2010, 16:04:16 »
i realized (in low light mode) when i half press the shutter, i see the iso values on the lower right corner of the lcd do something curious: upon the half-press, it shows the override value i have set in shdk. and then it reverts to the iso value the camera assigns as it refocuses or whatever. that gave me an idea - i go into the menu portion, and thought maybe i can disable that - so i tried disabling servo af.

FINALLY! it is now working! on the half press, i see my override iso value, and stays that way as i take the picture. i am absolutely beside myself...(i also downloaded the chdk for my trusty ol' sd750 to tinker with...)
OK, that's probably a bug. It's not uncommon for overrides to be missed in some cases.

It would be good to know if this happens only in low light or not ?
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one curious question though. suppose i set shutter speed override to 1/30. it comes out as 1/30 on the shot details. BUT on the iso, it's a little 'off.' if i set it to 50, the shot is taken at 80. at 100, it takes the shot at 160. it's exactly 60% more. why is that?
Canon has "market" ISO and "real" ISO, which may explain this difference. If you want to know why, ask canon's marketing dept ;)

If you are using low light mode, it may get more confusing, because the camera will call it something like ISO3200 but not all of that is done by adjusting sensor gain (which is the normal definition of digital camera "ISO"). The even applies to the higher ISO settings of cameras that don't have a specific high ISO or ISO3200 mode, e.g. canon firmware has ISO400 and ISO800 but raw is the same for both and the real difference is somewhere in jpeg processing.

Further warning, what is recorded in the exif isn't necessarily meaningful with CHDK overrides. Whether the exif value reflects what the camera actually did depends on the camera and setting. If you want to be sure the camera is actually doing something, you should evaluate the actual images.
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speaking of bugs, did i read correctly that the s90 chdk ONLY has beta versions?
True, although beta isn't clearly defined in CHDK ports. It usually means the port is new and/or some standard features are known to be broken.
Don't forget what the H stands for.


Re: does chdk specifically work in s90's low light mode?
« Reply #4 on: 01 / July / 2010, 19:02:56 »
Quote from: reyalp
OK, that's probably a bug. It's not uncommon for overrides to be missed in some cases.

looks like it might be. in auto mode, with the servo af turned on, overrides worked. similarly for av & manual modes.

so where can i request a fix for this, as i almost intend to exclusively shoot in low light mode thanks to the least amount of shutter lag?

yes, point well taken on the exif data. was pretty obvious though, even to a newbie like me, as to how different the pictures looked.

thanks again.

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Offline reyalp

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Re: does chdk specifically work in s90's low light mode?
« Reply #5 on: 01 / July / 2010, 19:30:35 »
I'd suggest posting in the s90 development thread http://chdk.setepontos.com/index.php/topic,4509.0.html

Make sure you post details of what canon and CHDK settings you are using along with what the expected and actual results are.
Don't forget what the H stands for.

Re: does chdk specifically work in s90's low light mode?
« Reply #6 on: 04 / July / 2010, 21:23:10 »
thanks, reyalp, will do.

 

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