DBK
LIFE MEMBER
Don't know if this has been covered but as a rule of thumb don't use a shutter speed slower than the focal distance of the lens if you are holding the camera by hand. For example, don't go slower than 1/500th of a second with a 500 mm lens and 1/250th of a second on a 250 mm lens. And so on. It isn't a hard and fast rule but go much further away from these speeds and blurred shots will probably result.