A rocky brook in the Columbia River Gorge. I found that using the HDR blending technique for creating the velvety look to the flowing water also allowed to capture the deep blacks and recover the shadows and avoid the technical issue of shadow noise.
Great shot Steve.......My POTD........Didn't think the 5D sr had noise problems. I am contemplating getting the 5d Mk IV in the next couple of months......
I can't really say that there is any noise problem greater than any average DSLR. The way that I do HDR's now greatly eliminates most noise anywhere because it is easy to stay in the parameters of the histogram. I probably do 75% of my HDR's manually by using Photomatix to align and merge the different exposures into a 32 bit image. I then will do my "tone mapping" in ACR to get close, then use the brushes in raw to refine the final image. Sometimes I will use various layers of the 32 bit image to bias to the strengths of various tone ranges then blend them in layers. There is a lot of specificity doing it this way. The only problem would be that occasionally the particular HDR effect ( surrealistic )becomes minimized as the image can be very accurate and less "artistic", although, a version of that can be layer blended into the more realistic version and get an interesting hybrid look.