RE: [OM] Long Focus vs. Mirror Lens

[Winsor Crosby]

> This is the case because these mirror lenses are solid catadioptric designs,
> and there's no place 'inside' to put a regular diaphragm.  Most have rear
> accessory threads for ND filters.
>
> -----Original Message-----
> From: Daniel J. Mitchell
The Oly lens diagram for the 500/8 does not show a solid design which 
is typical I think. I think catadioptric designs are very rare like 
the old Vivitar Series 1. You are right that an aperture mechanism in 
front of the primary mirror would be in the light path. I do not know 
enough about optics to know whether an aperture mechanism could be 
inserted into the light path behind the primary.
--
Winsor Crosby
Long Beach, California

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