What is the minimum shutter speed I should use to avoid blurry photos due to camera shake?
This depends upon a number of factors including the focal length, the steadiness of your hands, and vibrations caused by the mechanical parts of your camera, e.g., mirror slap in SLRs. If your lens has a (35 mm equivalent) focal length of X mm, then a good rule of thumb is to shoot at 1/X or faster. Small movements of the camera shift the image more at long focal lengths.
