Canon 7D Poor IQ - Banding

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Is anyone experiencing any banding/lines when post processing their images from the Canon 7D? I have been seeing lines/banding shooting at ISO100 and this are very apparent in many images in the sky/cloud areas. I never had this issue with a cheaper entry level camera. Is it normal, or a fault?

Here are some examples, all shot at 100ISO RAW, processed in Canon DPP. They were shot to expose to the right, and then underexposed and contrasted added to bring out the texture of the cloud detail.

http://www.tryanphotos.com/photos/820404906_uHdvQ-O.jpg
Mod note: Image over sized now URL