Archived posting to the Leica Users Group, 2000/11/09
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Hi Horst I think even the best small value caps can eventually die out. Most I believe are epoxy encapsulated and epoxy though very good for this app is not compleatly inpermeable indefinitely. I think only glass could do that. I'm talking in terms of serveral centuries. A metal blade FP mechanical shutter like that used on the R6 or S2 could easily last that long in normal use so long as the materials don't fatigue. I guess it's a contest between the chemical deterioration of electronic components and the fatigueing of mechanical components. The electronic shutter has both components but is very simple mechanically while the mechanical shutter is very complicated by comparison. I think the Industrial engineers invented the MTBF concept just for this sort of thing. I guess they would award the higher value to the electronic shutter and to the camera with a compleatly solid state metering system. See Ya Javier PS: It just ocurred to me. We still don't know the failure rate of silicon or MOS based devices past the first 50 years or so. So all our ideas on electronic reliability could be out the window. "A.H.SCHMIDT" wrote: > Martin Howard wrote: > > > Javier Perez jotted down the following: > > > > > There's only one type of electronic component that can reasonably be expected > > > to deteriorate in an electronically timed shutter. It's the capacitor or > > > capacitors that govern speed as a function of discharge rate. > > > > Oh really? What about the integrated circuits that have been popular in > > cameras with electronically timed shutters for the past 25 odd years? > > > > M. > > > > Javier. these days the timing capacitors don't deteriorate anymore. they either > use tantalum, or plastic insulated capacitors. Even electrolytic capacitors, which > are not normally used, because of the large initial tolerance, don't deteriorate > anymore. > > Regards, Horst Schmidt __________________________________________________ Do You Yahoo!? Talk to your friends online with Yahoo! Messenger. http://im.yahoo.com