P3D Mirror Lenses

["Lawrence A. Haines" <lhaines@xxxxxxxxxxxxxx>]

Does anyone have experience with long focal length lenses that use
mirrors ratherthan solid glass?  I notice 500 mm mirror lenses costing
about $100 each being sold new.  They are lighter and smaller in
diameter and in those regards would be very good for paired lens
stereo.  Offhand it would seem that the reflected light of the mirror
might reduce the available light, but I really do not know. Some of  the
store people I have talked to say they are not as sharp as regular glass
lenses, and yet there are those who say that if the lens is used at f 8
- 22, they are just as sharp as glass lenses used at the same openings.
I am interested in the experience of anyone who has used them.

Larry Haines
P.O. Box 1177
Eastsound, WA 98245
tel 1-360-376-4704
e-mail <lhaines@xxxxxxxxxxxxxx>


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