Archived posting to the Leica Users Group, 1997/07/25
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 09:50 AM 7/25/97 -0700, aglang@sprynet.com wrote: >Basic stuff, guys. >I dont know the specs on the R8, but I assume it has a focal plane shutter of >some sort, so the actual time the mirror is up will be a bit more than the X >synch speed. In the case of M cameras, this is 1/50 sec (the blitz mark). It is >the shortest speed for which the entire shutter is open at once. Shorter speeds: >1/60, 1/125, etc. have the second curtain released shortly after the first, so >that at 1/1000 you essentially have the two curtains moving accross the frame a >few mm apart. Each bit of emulsion is exposed to light for 1/1000 second, but it >taked 1/50 second to exposed the entire frame. > [snip] I like the general logic of this argument. 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. After all, if the mirror could be cycled faster, someone would have figured out that opening the shutter fully then flapping the mirror (a little additional light proofing would needed perhaps) would produce a faster X sync time. Manufacturers of FP shutter SLRs would have surely jumped on that one if it were possible. Best regards, David Seifert