Low ISO Noise with 20D???

[Toogy]

I have been noticing more shots lately at low ISO settings (ISO 100, 200, 400) that appear to have alot of noise in the them. I don't know if it is my imagination, but it seems to be getting worse.
I'll take a shot of some clouds in the sky @ ISO200 and notice that there appears to be LOTS of noise in the clouds.
Why?
Anybody else experiencing this? My friend that has a 20D told me he is noticing the same thing.
Here is a sample image of what we are talking about.

http://www.pbase.com/jinderv/image/44003803.jpg

[elbirth]

I think a 100% crop would be more helpful. Between the small resolution and jpeg compression, it's not as apparent.

[tim]

Yep crop needed, that's perfectly smooth. I sometimes run ISO 400 thru noise ninja, it can help a little, but it's not until 800 or sometimes 1600 that it's really necessary.

[scottbergerphoto]

The 20D has very low noise. My recent birding pictures in the Nature Section and my Jamaica Bay gallery at PBASE are all at ISO 800. The thing you have to remember is that you need to have the correct exposure to take advantage of that. If you underexpose a picture and then try to correct the exposure, you will get alot of noise. The picture you posted is underexposed. Shoot Raw and keep the histogram as far to the right as possible without clipping any highlights. You can then reduce the exposure to your liking in ACR or whatever Raw converter you like. Fully 1/2 of all the data of an image is in the first f stop at the far right of the histogram. When you underexpose, you lose data. Noise is created when the camera/raw converter tries to fill in the gaps for missing data.

[Wazza]

Noise will also become more apparent when underexposing. I generally expose neutral, or slightly under to regain some detail. Odd anyway, if it's getting worse. Or has the weather just been getting worse, with less natural light?

[foxbat]

Noise will also become more apparent when underexposing. I generally expose neutral, or slightly under to regain some detail. Odd anyway, if it's getting worse. Or has the weather just been getting worse, with less natural light?Here in England the weather's 18% grey all year round. :)

[Andy_T]

That would be at noon on a sunny day, right :lol:

Best regards,
Andy

[Simon Spiers]

Nice roll cloud Toogy!
Thunder did it?