Archived posting to the Leica Users Group, 2001/04/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]> >I'd be curious if you happen to have the acceleration curves and/or the > >open/close times for any leaf shutters? That would certainly > substantiate > >or refute the claim that it doesn't matter. My understanding that this > >phenomenon does matter is apparently standard knowledge, and has been > >discussed extensively on the Rollei and LF lists. > > Austin > > ALL mechanical shutters haver errors. It goes with the turf. But the > errors in mechanical shutters, or, at least, the better ones, are within > the permissible window the film will allow. If your shutter is off 1/6 > stop, it doesn't matter, so long as the film will allow a 1/3 stop window. > > Marc For the most part, I agree, and accuracy is obviously more important depending on what film choice you make. This is second hand information: The opening and closing of medium size late version Compur shutters takes about 1/1000 second total. For a #1 Compur the factory adjustment is to have a total open time at 1/500th of about 1/380th second. For shutters like the Compur Rapid, as found on Rollei cameras, the loss is around 20% to 50%, perhaps 1/3rd stop to 2/3rd stop at most. The effective speed for small stops for the Compur shutters used on Rolleis is around 1/380th for the speed marked 1/500th, providing the shutter is in good condition.