Re: PHOTO-3D digest 1195

[bobh@xxxxxxxxxxxxx (Bob Howard)]

RE: Life size viewfinders: Phil and others comments.
The comment came from viewing through a conventional Realist
viewfinder, which minimizes the scene to "get it all in" and was the
common "reversed telescope" finder found on all cameras with optical
finders, except a few Albada bright frame finders usually folding. In
1954 Leitz introduced the M3 Rangefinder camera with LIFESIZE viewing
and a bright frame like the Albada finder that allowed you to see a
bit beyond the picture area which was framed by a bright outline in a
slightly bigger field. This finder was truly lifesize and as a result
you could keep both eyes open and get a stereo image to boot with the
"frame" suspended in space.
The first SLRs that came in about 1955 (Contax S, Rectaflex, Exakta V)
had to use a 55mm lens to clear the mirror!! (All modern 50mm lenses
are so called 'retrofocus' from the Angineaux trademark of the first
SLR wide angle).
These cameras also were designed to give a life size image to the
viewer and both eyes could be kept open. In fact this was a design
feature of the Contax S which had a bright outline around the ground
glass. Because this was before the auto diaphragm or even preset stop
ring, the Contax S could not be seen though once you stopped down to
f/16 to take a picture. If you had the book you were told to open both
eyes and them see the "frame" in order to use the camera at stopped
down condition. Voightlander put out a cute finder that was black
field with a white dot in the middle and a frame line. People never
could get the hang of this..as they closed one eye. With both eyes
open you had a life size field with a frame hanging in space. I forget
the clever trade name they gave that finder. It will come to pme as
soon as I press send.
NO reason one could not make something similar today. THE ONE GOOD
optical viewfinder is the Keppler finder (has more elements than most
lenses).
It is in some Canons like the half frame Demi S. I have bought these
to extract the finder which is near Realist type..e.g. half frame.
BobH


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