Re: Anybody know where to get an SD-11 focusing screen?

[Joe Wilensky]

I have this screen for my MX and it's fascinating that depth-of-field 
preview doesn't work on this screen (the stopped-down viewfinder at 
smaller apertures just appears as smaller image circles with a sense 
of a not-high-enough eyepoint). Consequently, it seems near 
impossible to focus with this screen, and therefore it makes sense 
for astronomy photography where infinity is infinity and brightness 
is all that matters.

Does anyone have a good technical explanation as to why 
depth-of-field preview doesn't work the same way with this screen 
than with any of the matte ones?

Joe


As I understand it, the SD-11 is completely clear, not etched like a 
ground glass.  This produces the brightest possible image, which is 
what you want when focusing on the night sky.

Sam

--

Joe Wilensky
Staff Writer
Communication and Marketing Services
1150 Comstock Hall
Cornell University
Ithaca, NY 14853-2601
e-mail: [EMAIL PROTECTED]
tel: 607-255-1575
fax: 607-255-9873