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setting auto iso

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merielsea

setting auto iso
« on: 15 / June / 2012, 15:31:04 »
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Hi, i've been using chdk for raw photos for over a year and it's made me very happy, but I can't seem to get past hurdles to any other uses of chdk and the manual is not helping, so I'm in the forum. I want to limit my 1100d's auto iso so that it ranges only to 400 iso.  so I went into custom auto iso, then enabled auto iso, then entered into max iso auto "40" for 400 and then also entered "40" into max iso hi.

But still in auto iso my camera is going up past 400 to say 640. My camera is noisy past 400 so I thought I would try that adjustment.

really I'm just trying to learn the limits of chdk on my camera for many things but the only thing I've been successful at is "raw" which in itself is fabulous but I feel I am stalled at some level that would likely be easy to move past.

Hope you can help.

Re: setting auto iso
« Reply #1 on: 15 / June / 2012, 16:35:37 »
Hi, one thing to check is if you've got overrides enabled, otherwise CHDK does not override the default values even if you've got Custom Auto ISO enabled. Go to Main Menu -> Extra Photo Operations and check what the value of "Disable Overrides" is set to. If it's not set to "Disabled" then set it to this. Now when you shoot you should see "AUTO ISO" in the top left corner of the screen in red. Hope that helps  :)

Re: setting auto iso
« Reply #2 on: 15 / June / 2012, 18:06:53 »
But still in auto iso my camera is going up past 400 to say 640. My camera is noisy past 400 so I thought I would try that adjustment.
If you search this forum and the wikia for "market ISO" you will discover that the ISO published by Canon (and inserted into EXIF info) is somewhat inflated.   CHDK uses the "correct" ISO value that photographers the world over have used for at least 100 years.    However,  this obviously causes some confusion.

What happens if you limit the ISO to 200 ?  Do you see values closer to 300 but no higher ?

Update : played with this a bit.  The whole Custom Auto ISO menu is a bit of a mystery.  More info here :
http://chdk.setepontos.com/index.php?topic=8213.msg86438#msg86438
http://chdk.setepontos.com/index.php?topic=650.msg75555#msg75555
but I was able to clamp the max ISO to 100 by setting :

..
Max ISO AUTO (x10)   [ 10]
...
Second alternative max ISO(x  [    10]
..
Max ISO HI (x10)   [   20]
...



« Last Edit: 15 / June / 2012, 19:10:59 by waterwingz »
Ported :   A1200    SD940   G10    Powershot N    G16

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merielsea

Re: setting auto iso
« Reply #3 on: 15 / June / 2012, 19:32:08 »
Hi thanks for your replies, yes I am set to disabled already, and I tried changing the iso settings to 300 just to see what would happen, but nothing did. So I'm not sure the auto iso in chdk is doing anything. Perhaps there's some other setting that also needs to be activated.

I'm not sure what to make of the two links but I'll look at them further. Is there a way to set just some things back to default on chdk? Just the iso settings?

I'm going to be wading through all this for awhile before I understand the basics of chdk, but I taught myself photoshop so I'm confident I can find my way through this eventually.

I don't mind setting my own iso in some situations, but indoors it would be nice to set it on auto and cap it at 400 or 600 when it gets too noisy.

So I'm still hoping for words of wisdom on this auto iso though I may move on too to try to understand changing shutter speed and I don't think on my camera I can change aperture at all through any means except through zooming.


Re: setting auto iso
« Reply #4 on: 16 / June / 2012, 09:13:53 »
So I'm still hoping for words of wisdom on this auto iso though I may move on too to try to understand changing shutter speed and I don't think on my camera I can change aperture at all through any means except through zooming.

From this page: http://chdk.wikia.com/wiki/CameraFeatures it looks like the SD1100 IS has a neutral density (ND) filter rather than a diaphragm, so it would be expected that the aperture cannot be controlled. However, you should be able to get up to quite long exposure times with the shutter speed settings.

Is there a way to set just some things back to default on chdk? Just the iso settings?

As far as I know there isn't a way built into CHDK to do this. However, I think if you make a backup of the file CCHDK.cfg in the CHDK folder on your memory card, then delete from the memory card and run CHDK, the original settings will return again (for everything). Then you can use the CFGEDIT program (http://www.zenoshrdlu.com/kapstuff/zcfgedit.html) with your original config file to set the original ISO values that you see on the camera, before replacing the new file on the memory card with your original again. If that makes sense? There's probably a better way of doing it though.

Hope you get it working.

 

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