what is causing the noise?

ISO is 250 any suggestions? Thanks

How much did you crop it?

Idk if it is just me, but the 2nd and 3rd look sharp....no noise, or VERY little.

The 1st one does have visible noise, but not enough to be upset about...idk it seems like a good photo.

Maybe a better way to put it is that it's acceptable noise?!?

FWIW I kinda like the way the clouds look in #1, gives it a surreal look.

Thanks for the quick responces.
MWhite the 1st is about 50-60% crop the other 2 have very little crop. I like the clouds and haven't tried any noise reduction yet. just thought I might be doing something wrong. Just looking to much maybe.

Thanks for the reply Rolfe,I'm not upset glad you like them only trying to get better.

I shoot in non intermediate ISO's. At 250 your pushing ISO 200 in-camera. Did you adjust the exposure in post at all in #1?

The questions have already been asked but how much of a crop (already know the answer) and how much, if any, of an increase in exposure in processing.

To tell you the truth...I find the noise in #1 normal for a 40D considering the crop.

Thanks windpig and Duane, I made a curves adjustment to get more contrast and an increase with clarity. no sharpening. When the sky is clear I don't notice noise so I guess a cloudy background means less croping and PP. Some days it doesn't show some times their is to much. Thanks for the help.

Duane N wrote in post #13143834
The questions have already been asked but how much of a crop (already know the answer) and how much, if any, of an increase in exposure in processing.

To tell you the truth...I find the noise in #1 normal for a 40D considering the crop.

Agreed, what noise?