Quote Originally Posted by Max Power
Why bother with leaf shutters then? Is it because 75 years ago, they were the only way to go? Is it because you can incorporate shutter and aperture elements in one small package?
Why are they still used (there must be some advantage, no?) If focal-plane shutters can move at faster speeds, why not simply use them?
A focal plane shutter exposes a given point on the film for a shorter time. In operation, when the shutter is activated, the "first" curtain starts to move across the film opening. At a given time, the "second" curtain follows. That is not necessarily "faster". As the "slit" (actually the area separating the first and second curtains ) moves across the film, of necessity, there must be some distortion of the form of a fast moving subject. There is a specific time when the second curtain starts its movement only when the first curtain has uncovered the entire frame ... that is called the "mechanical" shutter speed, and it is the only speed where the light from a very fast "electronic" flash will reach the entire frame.

With a leaf shutter, electronic flash is suitable - synchronized - at any speed.