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Old May 12, 2006, 12:09 AM   #1
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Well as most will have worked out onthese threads,I got my 30d yesterday. I went out and shot a bit of wildlife and although the photos were good i was a little disapointed in the noise, not that it was really bad but going on the blurbs from Canon I expected nil. Anyway this morningI went out and shot more photos, I started off at ISO 400 again and then moved it up to ISO 500 and bingo, no noise. The shots that I used ISO 400 in are not as clear and noise free yet the ISO 500 ones are great, even in the dark areas of the photos. Why would this be the case?
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Old May 12, 2006, 1:42 AM   #2
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The only real possibility is that it is because you've underexposed the ISO400 shots and correctly exposed the ISO500 shots.
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Old May 12, 2006, 3:19 AM   #3
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I cant really see it but it doesn't matter, all I know is ISO 500 on my camera is pretty sharp and noiseless:-)



I got this answer from someone on another forum interesting re ISO.

Noise also depends on the situation. If you really want to test noise in real life, take the same shot at different settings.

Besides that, I've run a test with testing software with my 20D and apparantly, there is less noise in ISO 200 than in ISO 100!

So your observation may well be true.

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Old May 12, 2006, 7:53 AM   #4
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I tend to agree with peripatetic, you can get noise at lower ISO (even ISO100) if an image is underexposed
-> In real-life situation the exposures vary all over the place if one is not careful (especially if it's the camera who does all the 'evaluating')
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Old May 12, 2006, 10:13 AM   #5
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I agree, proper exposure is the key. Look at the histograms of your shots at ISO400 and ISO500 and you will see the difference.
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Old May 12, 2006, 12:24 PM   #6
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Or take same shots, at the same tame, different ISO ... camera on P or manual? I am taking pictures for years but always let the camera decide on exposure. Than if I want, I can adjust to desired or use +/- feature of the camera.

Or for the best check the exposure on the open hand or gray/white cardboard for the most accurate.

Anyhow, for the sake of testing I would leave camera on P. I think I can be less accurate than today's digital camera.

BTW, I always take my pictures with -3/2 exposure. I found the pictures to bright for my taste. Also, in digital, underexposed is always better than overexposed.


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Old May 12, 2006, 2:42 PM   #7
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Quote:
Also, in digital, underexposed is always better than overexposed.
I beg to disagree.

http://www.luminous-landscape.com/tu...se-right.shtml
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Old May 12, 2006, 3:45 PM   #8
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Hey can I play?

First, I agree with Peripatetic about exposure - over exposure is better especially from a noise standpoint up until you get to clipping details - then it's bad.

But, one other thought - does anyone know how Canon's in-camera noise reduction works? I'm not talking the custom function but in general. It's possible their algorithm behaves differently at different ISOs and a jump from say 400 to 500 might trigger more in-camera noise reduction. Just another thought.
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Old May 12, 2006, 6:38 PM   #9
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The ISO 50 rating for the 5D is noiser than the ISO 100 rating. That's why it's an expanded option verses being part of the standard 100 - 1600 normal ISO range. However, I tend to agree with peripateticthat there might be more noise due to exposure differences. I can't really tell if there is any noise in the ISO 400 photos taken with my 20D with adequate lighting.
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Old May 13, 2006, 2:13 AM   #10
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For those who are interested in the technical details and noise response of Canon sensors, you could try starting here...

http://www.clarkvision.com/photoinfo...phy/index.html


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