Mirror Lockup: When to Use It
Rose at Brookside Gardens (1/25sec, mirror lockup) Under most circumstances, having your camera on a good tripod will allow you to take sharp pictures. But when shooting with shutter speeds between 1/2sec and 1/60sec or so, the camera itself can cause a problem. Your SLR camera is equipped with a mirror that allows you to see through the lens of your camera before you take your picture. This mirror covers the sensor of your camera. Whenever you trip your shutter, that mirror has to get out of the way of the sensor, so it slaps up against the top of your camera. That action can cause vibrations in your camera. For fast shutter speeds, the picture is taken before these vibrations can cause an issue. For very slow shutter speeds, the camera is still long enough that these vibrations do not significantly effect the image. But somewhere in the range of 1/2sec to 1/60sec (actual values will vary based on your camera, lens and tripod...