As hinted at in my earlier response to jeff's later posting, the original
MTO-500 and MTO-1000 lenses were designed with 39mm screw mount for a 45.2mm
register, and manufactured at the Krasnogorsk plant.
By the late 1970s they had been redesigned to fit 42mm screw mount with a
45.5mm register. In that version "A" was added to the end of the
designation - theoretically becoming MTO-500A and MTO-1000A though I haven't
seen that confirmed. At that same time, production was moved to (I believe)
Lytkarino.
The MTO lenses are still made at Lytkarino, as well as Rubinars which look
different, both cosmetically (I haven't seen a Spiratone lens for many many
years, the Rubinars seem similar in appearance) and technically (Rubinars
seem to have a silvered zone on the rear of the front meniscus, rather than
a separate mirror). Images of the current production lineup can be seen
here:
http://www.lzos.ru/photo.htm
--
Piers
-----Original Message-----
From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On Behalf
Of Chuck Norcutt
Sent: 21 June 2006 21:20
To: olympus@xxxxxxxxxx
Subject: [OM] Re: 500/5.6 Rubinar / MTO Catadioptric lens
I found this a bit confusing. I well remember Spiratone and bought a fair
number of things from them in the late 60's and early 70's. I also remember
the Russian MTO and also the stories that the Spiratone 500 mirror lens was,
in fact, an MTO lens.
What confuses me is your comment about adjusting the mirror to move the back
focus out to make it suitable for an SLR. The implication is that the MTO
is a spotting scope rather than a camera lens. Maybe you're right but I
remember the MTO and Spiratone 500's as T-mount lenses and thus designed for
SLR use from the get-go.
OK, all you oldies out there (most of you except Ali), which of us is
correct?
Chuck Norcutt
Jeff Keller wrote:
> My interest got drawn into searching for info on the MTO catadioptirc
> lenses. I came a cross a statement that the Spiratone mirror lenses
> were actually MTO lenses. I can't find the original link but I found
> another that suggests there could be a connection. Fred Spira, the
> founder of Spiratone, apparently imported MTO lenses.
>
> http://www.beststuff.com/forum/read.php?21,31290,31310#msg-31310
>
> Has anyone had any experience with the 500/5.6 Rubinar or MTO lens?
>
> Apparently the quality varied dramatically but the good ones seem to
> have been good.
> Also it appears that the early MTO lenses had a shallow flange-back
> distance. The infinity focus could be readjusted to make them work
> with SLRs. If that is nothing more than moving the primary mirror
> closer to the secondary mirror, it would seem that the secondary
> mirror wouldn't be large enough to reflect all of the light back
> towards the camera. Has anyone seen any detailed info?
>
> Thanks,
> -jeff
>
>
>
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