 BetterPhoto Member |
shutter speed and camera setting what will happen if you take a flash photograph with shutter speed on my camera set two setting faster than the sync speed?
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Bob Cammarata |
The shutter will open and close faster than the duration of the flash burst. The result will be that all or a part of the frame will be black.
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Jon Close |
Virtually all 35mm cameras use a focal-plane shutter. It consists of 2 curtains, the back-edge of the first curtain travels across the film frame opening the shutter to expose the film, then the front edge of the second curtain follows to close the shutter. The duration of an electronic flash is very short, from 1/1000 to 1/10,000 second. It is triggered to fire when the 1st curtain has fully opened (or alternatively, just before the second curtain begins to close). At slow shutter speeds, the shutter curtains open fully on the entire film frame. But for shorter shutter speeds, the second curtain starts closing before the first curtain is fully open. This creates an open slit that travels across the film frame exposing a portion of the frame at a time. So for a shutter speed of 1/1000, even though each portion of the film frame is exposed for just 1/1000 of a second, but it may take 1/250 to 1/60 second for the open shutter to cross and expose the entire frame. So a flash fired when the first curtain has fully opened will only provide light to that portion of the film that the second curtain hasn't already covered. The flash sync speed is the shortest shutter speed for which the curtains are open on the entire film frame.
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