Using a telephoto lens to get in close to the action or sneak up on a subject from a discreet distance is terrifically exciting, and can yield great pictures. But the high magnification of long tele and zoom lenses accentuates the effects of camera shake caused by your inability to hold the camera and lens absolutely still. The effects of wind, moving or shaking floors, residual vibration from camera mirrors flipping up just prior to exposure, atmospheric haze, and heat waves can also add problems.