Help, Excessive Image Grain

Hi, I have posted this image as I am currently having problems with excessive grain/noise in my images. This image was shot with a Canon 50d and 100-400 lens. 1/250 at ISO 250 app 7.1 and underexposed by two stops. I have increased exposure in the canon software, Contrast +1 and sharpening was set at 3. I would be interested if anyone has any ideas as to what I'm doing wrong. The lens has been sent back to canon for recalibration but the raw image looks very grainy as a raw image.

Many thanks in advance.

Scott

Hi Scott

The key phrase for me in your description is

I have increased exposure in the canon software

If you under-expose in the camera and then try to rectify this in software, you will almost inevitably increase noise in the images

Barrie

I aggree with Barrie

I,m not a Canon man but the same applies to Nikon. Any under exposure is where the noise starts to show first.
JR

As Barrie and John have pointed out, you need to set the correct exposure value in the camera to minimise image noise. It isn't really clear from your post though whether the 2-stops of under exposure was due to pilot error, or an intentional action to prevent the highlights from blowing out. In any case, the files from the 50D are rather "gritty" when you look at them at full resolution, even when the image is exposed correctly, but the images look fine when printed. The image as posted also looks OK to me. There certainly isn't a lot of objectionable noise evident and I'm pretty sure that this would look OK in print. There are a few areas in the posted image where there maybe some jpg artifacts produced by the file compression process. If you are concerned about the "grittiness" of the image files produced by the camera I would urge you to check the printed image. If you are still concerned you may find that noise reduction software such as Noise Ninja, Imagenomic, or Nik Define will give you results that you are happier with.

I doubt very much that the lens is responsible for what you are seeing.

Hope this helps.

Second that
JR

The only thing I can add to the above comments which are surely the root of your problem is that I find the noise levels on my 40D at iso 250 are more like those of iso 400 than 200. If you were using a tripod, it might have been worth dropping to iso 200 as well. Under -exposure is the kiss of death as far as noise goes in my opinion.
eric

Hi, many thanks to Barrie, John, Phil and Eric! I have done a few test shot this morning, shooting at -2, -1 and 0. When blown up to 200% the level of noise in the -2 image are very, very noticable. I think that you could possibly get away with under-exposing a little but from now on I will be using other methods!

Thanks again.

Scott