Archived posting to the Leica Users Group, 1997/07/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]>Given that top X sync speeds >have been hovering around 1/250 for more than a decade (yes, I know the F5 >can do 1/300 in a special mode) it seems that the mirror cycle time may be >the limiting factor. David, The limiting factor is the speed of the shutter curtains. Most of the really fast shutters travel vertically, so they only need to travel the length of the short side of the film. One of the big mechanical difficulites is that both curtains need to travel at exactly the same speed, so that as the second curtain follows the first, the distance between them stays the same. They also need to instantly accelerate and instantly stop, without bouncing. The top flash sinc speed gives you an indication of how fast the curtains move--if the sinc speed is 1/250 of a second, it will take slightly less than half of that time for each curtain to move across the frame. - - Paul