Archived posting to the Leica Users Group, 1997/07/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]At 07:41 26/07/97 +0000, you wrote: >> Richard Clompus wrote: >> > I think the EOS1n RS (hard to keep up with the abbreviations) >> > loses about 1/2 f stop due the pellicle mirror. I am sure Leica >> > could build one that only lost 1/4 to 1/3 f stop with a pellicle >> > mirror. > >Turns out that the Leicaflex SL was a step in that direction. The >caption to the cutaway drawing in the 15th ed. of the Leica Manual >notes that the presence of a semitransparent mirror which allowed 20% >of the light to pass through to a second mirror which redirected the >light to the metering cell at the base of the body. Apparently, >then, the conversion of the SL to house a stationary pellicle mirror, >as occasionally speculated upon here, would deactivate the ttl >metering capability. > Roy C. Zartarian I don't see why. If 20% of the light passes through the existing SL mirror and is measured by the ttl metering, proportionally more light would pass through a stationary pellicle mirror, so all that would be needed for that ttl metering to function would be the appropriate recalibration of the metering sensitivity to allow for the more transparent mirror. (Or even that crude device- altering the ISO setting!) Joe Berenbaum