[Leica] Mirrors (formerly is that a Visoflex?)

[lrzeitlin at gmail.com (Lawrence Zeitlin)]

George writes:

"Well it certainly would be reversed if looking through only the one mirror.

However that 45? finder would have to have a second mirror

which would bring it back around."

- - - - - -

Most reflex finders, including the Visoflex, are used with a lens. The lens
image is reversed, left to right, top to bottom. Think of the image on a
studio camera with a ground glass back. In a normal waist level reflex
finder such as in a Rollei, the top of the lens image is reflected by the
bottom of the mirror to the forward edge of the ground glass, the bottom of
the lens image is reflected by the top of the mirror and is now on the back
edge of the ground glass. The right side of the image, actually the left
side of the real scene, is reflected by the right side of the mirror and to
the right edge of the ground glass, the left side of the image to the left
side of the mirror and to the left side of the ground glass. So the image is
essentially rectified, as far as the viewer is concerned, top to bottom but
not left to right. A second mirror, arranged at a 45 degree angle to the
first in periscope fashion, would simply reverse top to bottom, not left to
right. The viewer would see the image just as the lens formed it. The top of
the real scene would appear on the bottom, the left on the right, etc.


Mirrors can be used to rectify the scene but they are not arranged like a
periscope. The Pen SLR used three mirrors instead of a prism. One reversed
the lens image top to bottom, another left to right, and the third changed
the direction to horizontal. The pentaprism used on most SLRs does the same
job in a single complicated piece of glass. It can also be done by a pair of
right angle prisms or a roof prism, as in most binoculars. But it can't be
done with only two flat mirrors.


Larry Z