Currently I my 600D's Main Dial is pretty stiff. Sorry I am not too sure how to call it, but the camera manual listed it as "Main Dial". It is the "ring" which you turn to change aperture/shutter speed, located just behind the shuttle button. Mine has gotten pretty stiff and is getting harder to turn and I am not sure if there can be anything done about it?
Canon said they dont recommend putting any lubricant though... is there any other way to make it smoother?