"On the old trick of matching the minimum shutter speed to the focal length of the lens (400mm = 1/400, 500mm = 1/500, etc.), keep in mind that if you're using a camera with a crop sensor you should probably consider the "equivalent focal length," (400mm lens on a 1/6 crop body = 640mm = 1/640 shutter speed)."

Hey Bob,

I have heard that said before, but I never understood why having a smaller sensor would make the camera more prone to camera shake. Do you have any thoughts on that?

James