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12-28-2013, 05:44 AM   #1
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M39 to P67 adapters?

Hi,
On Ebay, I found in several occasions China-made "Leica Visoflex M39 adapter for Pentax 6x7"-offers.... Do you think they could be used, perhapes combined with extension tubes, with enlarger lenses (as they mostly use M39 threads) for close-up photography? I think, using enlarger lenses should produce great close-up photos, as they are corrected for very good picture flatness... I am just asking this before ordering one. I donīt want to use Leica lenses, but enlarger - lenses for macro pupose...
Thanks for your advice!

12-28-2013, 05:56 AM   #2
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Wouldnt the image circle be a problem?
Also, be careful with M39. There is the leica M39 (LTM) and the Soviet M39. They have the same diameter of the screw mount, but a different pitch and might have different register distance. They are not compatible. So make sure the adapter will work for the lenses you want. There were cases on this forum where people wanted to use Leica lenses on Soviet M39 adapters and it didnt work. I think there were some threads on this, feel free to search.
12-28-2013, 06:10 AM   #3
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Hi,
I guess the image circle should not be a problem since 6x7 compatible enlarger lenses are used (i.e. 80mm and "longer")? You are mentioning the difference of Leica and soviet M39 thread... of what kind are the enlarger lenses?
12-28-2013, 07:11 AM   #4
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Most enlarger lenses are M39 (39x1)

How to use... Enlarger lenses | Amateur Photographer

AFAIK the only difference between LTM and the Soviet M39 is the flange distance.

12-28-2013, 07:20 AM   #5
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You might find some helpful information in this thread.
link
12-28-2013, 07:50 AM   #6
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THANK YOU VERY MUCH for your replies and the posted links!!
12-28-2013, 08:37 AM   #7
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https://app.box.com/s/fdee986cccb6ea2d08cd

The Leica M39 thread is a hybrid metric / turns-per inch thread 39 mm outside diameter and 26 turns per inch of 55 degree Whitworth thread form
I made an M39 adaptor in the lathe for the Pentax Bellows M.

The images are very sharp, but I found the enlarger lens is prone to flare and loss of contrast in sunlight - I did not use a hood which is likely to fix that.

The Pentax Bellows M will not be large enough for P67, so you will need some means of focussing.
The P67 register is 84.95mm so if the adaptor is less than 5mm thick including focussing, a 90mm enlarger lens will work, otherwise a longer focal length will be needed
12-28-2013, 10:01 AM   #8
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Pentax made a 49mm (and 67mm) reverse adapter for the 6x7 system. This allowed you to reverse 35mm Takumar lenses with a 49mm filter thread and use them on your 6x7 camera for macro work. The adapter was intended to also be used with the helicoid variable extension tube, which you used for focusing.

http://c758710.r10.cf2.rackcdn.com/files/support/manual/158_1314744928-1040057743_manual.pdf

Phil.

12-28-2013, 12:11 PM   #9
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QuoteOriginally posted by Na Horuk Quote
Also, be careful with M39. There is the leica M39 (LTM) and the Soviet M39. They have the same diameter of the screw mount, but a different pitch and might have different register distance. They are not compatible.
Truly? Which Soviet M39 is this? I am familiar with M39 (LTM) and M39 (Zenit SLR). Both are the same except for registration distance. Is there a third?


Steve
12-28-2013, 01:25 PM   #10
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QuoteOriginally posted by stevebrot Quote
Is there a third?
Nope. I might be wrong, but I read on various forums that the thread pitch is slightly different between the LTM and the Soviet mount (as you call it, Zenit). This causes the fit to be at least tight if not impossible. This is what I meant, beside the register distance. But please, share your experiences, I havent had the luck of testing out many Zenit and Leica lenses on various 39mm adapters.
12-28-2013, 02:42 PM   #11
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QuoteOriginally posted by Na Horuk Quote
Nope. I might be wrong, but I read on various forums that the thread pitch is slightly different between the LTM and the Soviet mount (as you call it, Zenit). This causes the fit to be at least tight if not impossible. This is what I meant, beside the register distance. But please, share your experiences, I havent had the luck of testing out many Zenit and Leica lenses on various 39mm adapters.
The term M39 (Zenit) is pretty well accepted and widely used. Other variations are Z39 and ZM39. I have never heard of the "Soviet mount". After all, the Soviets made cameras in many different mounts.

There are multiple discussions on the Web including a thread on the rangefinder forum (in which I took part) where the various types of M39 mounts are discussed. Here is a summary of my understanding by thread pitch and standard:
LTM and Zenit: 26 tpi Whitworth
Early FED rangefinder*: 1 mm DIN
Early Canon rangefinder: 24 tpi
That being said, there are some claims that all FSU 39mm lenses have 1mm pitch. I don't have access to a huge selection of lenses and/or bodies nor am I able to measure the threads on the lenses and bodies I do have access to, so I can't say with any certainty.

One thing I do know is that my FSU 39mm thread-mount rangefinder lenses fit both my FED and Zorki cameras and swap nicely onto my Canon P body (as standard a LTM body as you might ask for) with no binding or looseness.

M39 lens mount - Wikipedia, the free encyclopedia

L39 vs M39...What's the difference? - Rangefinderforum.com

A Google search using "M39 (Zenit)" will return many, many references including a few where people have tried Zenit lenses on their rangefinder cameras and vice-versa.


Steve

* The very earliest FED lenses/bodies are not cross-compatible with early Barnack Leicas. I don't have the details but it is my understanding that registration distance was the issue. The 1mm thread claimed in the Wikipedia is unsupported by a citation.

Last edited by stevebrot; 12-28-2013 at 03:22 PM.
01-04-2014, 02:06 PM   #12
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Instead of extension tubes I would suggest getting an M39 macro bellows to attach to the adapter. I see them on eBay quite often.
01-27-2014, 08:35 AM   #13
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I think you missed out the part that says "visoflex". That is the odd device Leica made that was mounted in between the lens and the camera and turned the whole thing into an SLR camera with a view direct through the lens. It adds 41mm to the total registration distance, so dedicated visoflex lenses could not focus to inflnity without the visoflex-extension-mirror-prisma device.

Still it is puzzling what the intention of this adapter is. There are other visoflex adapters to SLR cameras such as Pentax K, Canon FD and EOS or Nikon F, which allow focus at infinity. But the m39 Leica registration distance + the visoflex 41mm stil doesn't add up to the Pentax 67 registration distance. So no infinity focus.
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