[LRflex] Re: Maksutov-Cassegrain on R4
- From: David Young <dsy@xxxxxxxxxxxxxxx>
- To: leicareflex@xxxxxxxxxxxxx
- Date: Wed, 11 Aug 2010 07:11:07 -0700
At 07:54 PM 10/08/2010, you wrote:
>I've got a Russian KMZ (Soviet) made f:8 500mm MTO
>Maksutov-Cassegrain lens I thought I would put in front of my R4
>just for kicks. Yea, yea, I know about bokeh donuts and all that -
>this is for fun, not for serious. I've got a M39 to Leica R
>adaptor coming in from China as I write this. This 1950's circa MTO
>is threaded for M39. I'm not sure I'll get infinity focus - but, oh
>well, it's my only telephoto till I can afford something nice and Leitz.
>
>So... Here is my goofy question. As the lens does not have f stops,
>I assume I use the camera in (m) manual mode and match up the speed
>with... f:8 - right? The lens comes with a neutral density filter I
>could use in place of smaller stops if needed. Anybody ever done this before?
>
>Rob
Hi Rob!
I bought an MTO back in 1997, to use to photograph the sun, during
the 1998 solar eclipse. The normally low contrast of the any
catadioptric (mirror) lens was not a problem in this very
high-contrast situation. The images looked pretty good, and I have
11x14" prints on my downstairs wall.
My example was acceptably sharp but rather short on detail (low resolution).
This last spring, I purchased a Reflex Nikkor 500/8 which had been
modified to fit Leica R. It is noticeably sharper than the MTO, but
not what I'd call "a stunner". Again, lower contrast (though not as
low as the MTO) but with digital, this is easily fixed when
processing the RAW images. The fine detail (resolution) is better
than the MTO I had, but still wanting, compared to Leica (and most)
prime lenses.
The "donuts" can be a problem, but need not be, if you choose your
lighting and angles carefully.
Three examples are here:
http://www.furnfeather.net/Temps/Warbler.html
http://www.furnfeather.net/Temps/Warbler2.html
http://www.furnfeather.net/Temps/Squirrel.html
You should be able to use the lens in "A" mode, for no matter what
aperture the camera thinks it's using, it will set the shutters speed
according to the amount of light it "sees" coming in.
I used my MTO in "A" mode, successfully, with my R3 and R5 and the
Reflex Nikkor in "A" mode with my Oly E3.
You might even find that you can get infinity focus with the M39
mount.... as all mirror lenses will focus beyond infinity. This is
to allow for thermal expansion, which affects them more seriously
than normal lenses. So, at least at "normal" temperatures, it
*may* work! Give it a try!
As for your ND filter question... yes, they're intended to be used
instead of smaller stops... but I've never known an MTO user to need
them... The f8 aperture is more like f9 or f10, with the central
disc which holds the secondary mirror blocking the view. Over
exposure, with all but the fastest films is not likely.
These are not lenses for serious work, but they have a LOT of reach
and the cost is low. No doubt about it, they're fun toys!
Enjoy! And show us your results, will you?
Cheers!
-------------
David Young - Photographer
Logan Lake, BC, Canada
Wildlife & Sports: www.furnfeather.net
Personal pages: www.main.furnfeather.net
A micro-lender through KIVA.org.
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