Ruth
I've been unable to contact you off list. Please let me know how much you
are asking for the lens.
Cheers!
Dave Shupe
kc7iek@xxxxxxxxx
Latitude 47° 43' 1" North, Longitude 122° 6' 15" West
-----Original Message-----
From: owner-olympus@xxxxxxxxxxxxxxx [mailto:owner-olympus@xxxxxxxxxxxxxxx]
On Behalf Of Howard
Sent: Friday, February 01, 2002 6:14 AM
To: olympus@xxxxxxxxxxxxxxx
Subject: Re: [OM] Long Focus vs. Mirror Lens--FS
I have one of these "very rare" solid catadioptric lenses---the 600mm
Vivitar Series 1 Cat that I would like to sell.
Please contact me off-list if interested. Thanks!
Ruth Howard
----- Original Message -----
From: Jim Brokaw <jbrokaw@xxxxxxxxxxx>
To: <olympus@xxxxxxxxxxxxxxx>
Sent: Thursday, January 31, 2002 11:18 PM
Subject: Re: [OM] Long Focus vs. Mirror Lens
> on 1/31/02 1:09 PM, Daniel J. Mitchell at DanielMitchell@xxxxxxxxxxxxx
> wrote:
>
> >> This is the case because these mirror lenses are solid catadioptric
> > designs,
> >> and there's no place 'inside' to put a regular diaphragm.
> >
> > Ah, that makes sense. Is the Zuiko 500mm mirror not solid, and thus
> > lighter? 11oz isn't all _that_ lightweight, after all. (I'd look on
esif,
> > but..)
> >
> > -- dan
>
> Most mirrors are 'hollow' but due to the folded light path, there isn't a
> way to put in a aperture mechanism. There have been faster mirror lenses
> made, but the diameter of the whole thing goes up, and there are optical
> considerations in the shape of the mirrors that are affected by that. The
> actual aperture (t-stop) of a mirror us usually somewhat smaller than the
> f-stop due to the little secondary mirror blocking some of the front
> opening. I have a truly solid catadioptric lens, made by Vivitar, and its
> extremely small for its focal length, but being a solid lump of glass it
is
> very heavy for its size. The one advantage of the truly solid design is
that
> the mirrors, being the ends of one lump of glass, stay in alignment. The
> alignment of mirrors in a mirror lens is critical, and this is one area
> where low cost mirrors can fall down some... the 500/8.0 Zuiko is much
more
> solid that the $125 mirror lenses I've ever seen. It is not more solid
than
> my 600/8.0 Vivitar Solid Cat though, but it is about 1/3 as heavy... I
also
> have a 300/5.6 mirror (says Celestron but I bet the others are all made by
> the same factory) that is smaller in diameter and length than my 100/2.0
> Zuiko, and much much smaller than the 300/4.5 lens. The tradeoff is the
> fixed aperture and the speed, but for what it does it works well. The cost
> is about 1/3 the Zuiko also, if you don't use a 300 or 500 much that is a
> consideration.
> --
>
> Jim Brokaw
> OM-1's, -2's, -4's, (no -3's yet) and no OM-oney...
>
>
> < This message was delivered via the Olympus Mailing List >
> < For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
> < Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
>
>
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
< This message was delivered via the Olympus Mailing List >
< For questions, mailto:owner-olympus@xxxxxxxxxxxxxxx >
< Web Page: http://Zuiko.sls.bc.ca/swright/olympuslist.html >
|