ISO; 300D vs 30D and 20D

[PEACHMAN]

I got some grainy photos shooting at ISO 800 this weekend and it has been brought to my attention that the 300D does not produce the same results at these ISO's as the 30D and I assume the 20D(?)...I thought they used the same processor ?? Antbody out there that can streighten me out on this??

[Mikelangelo]

The 300D is a 6 megapixel CMOS procoessor. From what I understand, the 30/20Ds handle higher ISO settings much better. The 20D and 30D DO share the very same CMOS processor, tho'... so it should be virtually identical results with those cameras.

[Steve Parr]

I used to shoot with the 300D but, when I got into concert photography, I needed something that would perform well at higher ISO's (800+). The 20D and 350 were comparable, but I went with the 20D, primarily, because it's physically bigger and fit my hands better.

In my experience, the 300D is downright offensive at an ISO over 400.

If a new body isn't something to consider, you could always go the Neat Image route (noise reduction software). I've had pretty good results with that...

[nitsch]

30D/20D perform better than 300D. I'm with Steve, I don't like the results of the 300D above ISO400, however I quite happily use the 30D at ISO800. The 30D performs identically to the 20D AFAIK however the advantage of the 30D is that you can choose ISO in 1/3 stops - I like this as there are times when you need more than ISO400 but on the 20D you would be forced to leap a whole stop to ISO800 wheras on the 30D ISO500 and 640 are available and if they will suffice then the noise performance is better than pushing it to 800. HTH!

[PEACHMAN]

Well , I guess I'll be getting that 20D out a lot more and the 300D a lot less...Thanks for the confermation folks...And 1/3 stops of ISO in the 30D ? I guess that makes more sense than 2X stops...

[peterdoomen]

Yes, the 20D performs quite well in low light and high ISO.
(See for example the results of a show shooting I posted on http://photography-on-the.net/forum/...d.php?t=133041)

P.

[Tee Why]

No, the 10d/300D use a Digic I processor and have the same IQ.
The 20D/30D uses a diff. sensor and digic II processor. The high ISO noise is a small bit lower.
Here is a noise comparison by dpr of 10D and 20D which should be the same as 300D vs a 30D.
http://www.dpreview.com/reviews/canoneos20d/page20.asp
There is some diff. at ISO 800 and up but I really don't think it's much.

[mbellot]

Originally Posted by nitsch

The 30D performs identically to the 20D AFAIK however the advantage of the 30D is that you can choose ISO in 1/3 stops - I like this as there are times when you need more than ISO400 but on the 20D you would be forced to leap a whole stop to ISO800 wheras on the 30D ISO500 and 640 are available and if they will suffice then the noise performance is better than pushing it to 800. HTH!

I've read numerous time that the 1/3 ISOs are "faked" in the 30D and you can get the same effect on the 20D with exposure compensation and some tweaking in PP (ISO500 would be ISO400 with -1/3EC pushed +1/3 in PP, assuming you're shooting RAW).

I've never seen any actual tests/data to back it up, but it makes sense.

[nitsch]

Originally Posted by mbellot

I've read numerous time that the 1/3 ISOs are "faked" in the 30D and you can get the same effect on the 20D with exposure compensation and some tweaking in PP (ISO500 would be ISO400 with -1/3EC pushed +1/3 in PP, assuming you're shooting RAW).

I've never seen any actual tests/data to back it up, but it makes sense.

Very true, but it's a hell of a lot less PP to be able to do it in camera!

You can use the term "faked" if you wish, but what you definately cannot say is that it is just the 1/3 stops in the 30D which are "faked". If you want to use the term "faked" then you must use that term for ALL ISO settings above the native ISO of the sensor on ALL digital cameras. Increasing the ISO in a digital camera is NOT the same as using different film speeds; an ISO400 film is actually twice as sensitive to light as an ISO200 film, however when you switch your digicam from ISO200 to ISO400 your CMOS/CCD has not changed in sensitivity, the signal from the sensor is merely being amplified - you can call this "faking" the ISO value if you wanted I guess, and you are right in saying that there is no reason why you can't do this in the RAW conversion rather than "in camera", but remember this is the same for every digital camera, not just the 30D! HTH!

[syntrix]

I thought my 20D had the 1/3 stop option in the Cn menu. Hmmmm.

[adas]

Yes, but only for aperture and shutter, not ISO.

[syntrix]

Ahhh, that's right!

[mbellot]

Originally Posted by nitsch

Very true, but it's a hell of a lot less PP to be able to do it in camera!

No argument at all, and if you're shooting jpeg its a big plus.

Its also nice since (I assume) you still have the +/-2 EC that the 20D has already. Though you could get into some interesting numerical twists... Is shooting at ISO500 with +2/3EC more or less noisy than ISO800 (and so on, ad nauseum).

Originally Posted by nitsch

You can use the term "faked" if you wish, but what you definately cannot say is that it is just the 1/3 stops in the 30D which are "faked". If you want to use the term "faked" then you must use that term for ALL ISO settings above the native ISO of the sensor on ALL digital cameras. Increasing the ISO in a digital camera is NOT the same as using different film speeds; an ISO400 film is actually twice as sensitive to light as an ISO200 film, however when you switch your digicam from ISO200 to ISO400 your CMOS/CCD has not changed in sensitivity, the signal from the sensor is merely being amplified - you can call this "faking" the ISO value if you wanted I guess, and you are right in saying that there is no reason why you can't do this in the RAW conversion rather than "in camera", but remember this is the same for every digital camera, not just the 30D! HTH!

Well, sort of.

My understanding was that the full stops actually changed analog multipliers (opamps) while the 1/3 stops were handled in the digital domain.

If the 30D actually adjusts the gain on the opamp in 1/3 stop increments then I would consider that "real" ISO. Doing it after the A/D conversion is what I thought was happening and why I called it "fake".

[Titus213]

Peachman - I still use my 300D and don't mind using the higher ISO. I also use Neat Image Pro. The 20D does handle the higher ISO better IMO but the 300D is quite useable. I think the main trick is to get proper exposure as any under exposed image will show some noise. Here's a link to some interesting test results from DPReview. The 300D is a bit long in the tooth at this point so the comparisons are not with current equipment.

http://www.dpreview.com/reviews/canoneos300d/page13.asp

[solinger]

Higher ISO gets grainy when you miss the exposure a little. My 300d is fine at higher ISO but I am not as picky about noise as some. I can try to dig up an 800 ISO shot I took right after I got my 300d that impressed me.