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Canon G2 and auto-ISO setting -- what rules does it follow?

 
 
John Faughnan
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      04-10-2004
I usually set my G2 to ISO 50-100, up to 200 if I'm in marginal light
conditions (400 is too noisy with this camera).

There's an auto-ISO setting. I can't figure out rules it applies.
Logically the camera should look at the flash setting, and then adjust
ISO to maintain shutter speed > 1/30 sec (for example). It doesn't
seem to do this.

OTOH, I think the internal flash works better with auto-ISO
(presumably camera shoots at ISO 50 then?). That's important, since
flash exposure with the built-in flash on the G2 is not good.

Any suggestions?

john
http://www.velocityreviews.com/forums/(E-Mail Removed)

PS. I do like the camera quite a bit. I won't replace it until
Canon/Nikon/SONY offers me 6mpixel, excellent image quality (no
fringing, etc), ISO 800 with tolerable noise, similar non-SLR form
factor with the "flippable" viewer, JPEG2000 on camera, faster cycle
time, throughput and recovery time for about $500 US. None of this is
technically challenging at all ... more a matter of marketing
decisions ... but of course marketing decisions are much less
predictable than technology decisions ...

meta: jfaughnan, jgfaughnan, Canon G2, G3, G1, exposure setting, ASA,
ISO
 
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Don
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      04-10-2004
I have a G2 also, and also have never been able to discern the algorithm
used for auto-ISO. What I have found, though, is that if you shoot RAW,
it's best to just lock the ISO 50 setting in. The higher ISOs simply boost
the gain in the electronics prior to (or more likely during) digitizing the
CCD output. By saving RAW, you preserve the 12-bit depth of data which is
sufficient to do the same thing in post processing.

The only drawbacks I've found to that are the larger file sizes compared to
JPEG, and an apparent increase in the camera's refusing to shoot in low
light, for which it's notorious anyway, and of course the need for more
frequent post-processing.. None of these particularly bother me since I use
two 1GB cards and travel with either a laptop or a digital wallet, and
normally post-process everything anyway.

I also feel the way about the camera that you do.

Don


"John Faughnan" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) m...
> I usually set my G2 to ISO 50-100, up to 200 if I'm in marginal light
> conditions (400 is too noisy with this camera).
>
> There's an auto-ISO setting. I can't figure out rules it applies.
> Logically the camera should look at the flash setting, and then adjust
> ISO to maintain shutter speed > 1/30 sec (for example). It doesn't
> seem to do this.
>
> OTOH, I think the internal flash works better with auto-ISO
> (presumably camera shoots at ISO 50 then?). That's important, since
> flash exposure with the built-in flash on the G2 is not good.
>
> Any suggestions?
>
> john
> (E-Mail Removed)
>
> PS. I do like the camera quite a bit. I won't replace it until
> Canon/Nikon/SONY offers me 6mpixel, excellent image quality (no
> fringing, etc), ISO 800 with tolerable noise, similar non-SLR form
> factor with the "flippable" viewer, JPEG2000 on camera, faster cycle
> time, throughput and recovery time for about $500 US. None of this is
> technically challenging at all ... more a matter of marketing
> decisions ... but of course marketing decisions are much less
> predictable than technology decisions ...
>
> meta: jfaughnan, jgfaughnan, Canon G2, G3, G1, exposure setting, ASA,
> ISO



 
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John Faughnan
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      04-11-2004
"Don" <(E-Mail Removed)> wrote in message news:<(E-Mail Removed)>...
> I have a G2 also, and also have never been able to discern the algorithm
> used for auto-ISO. What I have found, though, is that if you shoot RAW,
> it's best to just lock the ISO 50 setting in. The higher ISOs simply boost
> the gain in the electronics prior to (or more likely during) digitizing the
> CCD output. By saving RAW, you preserve the 12-bit depth of data which is
> sufficient to do the same thing in post processing.


Ahh, that's verry interesting. It explains a lot. RAW is too much
post-processing work for me, but this emphasizes again why it's the
way to go for higher level photography.

What digital wallet do you use? I normally travel with my iBook, but
I've thought about buying a dig wallet as well. (Too bad the iPod
doesn't do a better job of this -- that was my biggest iPod
disappointment).

Great to know there's another G2 fan out there who wants the same
replacement camera I'm hoping for ... 6mpixel, excellent image
quality (no fringing, etc), ISO 800 with tolerable noise, similar
non-SLR form factor with the "flippable" viewer, JPEG2000 on camera,
faster cycle time, throughput and recovery time for about $500 US.

john
(E-Mail Removed)

meta: jfaughnan, jgfaughnan, Canon G2, G3, G1, exposure setting, ASA,
ISO
 
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