Mounting Schneider/Nikkor/Bronica lenses in Mamiya Press-helicoid?
Hi all - new to the forums. I originally posted this in the Mamiya Super 23 flickr group, but got no response, maybe someone here has any experience?:
I found a very interesting topic on photo.net about adapting Bronica (and other lens elements) to the Mamiya press helicoid, as they are designed for a standard copal 0 shutter.
I also found this example of an Schneider 150mm Xenar 5.6 lens, inserted into a Mamiya 150mm:
And this with a Schneider Xenar 4.5:
I understand that you lose rangefinder focusing with the modifications described on photo.net (Bronica lenses), but does the same apply to these Schneider adaptions? Does anyone know how much work this requires, and have any experience with it?
Could I mount e.g. this multicoated Nikon 150mm 5.6 in an Mamiya 150mm mount, or is the throat of the focusing helicoid too narrow? Even if lose rangefinder focusing, I still think it could be useful with an updated lens for landscapes e.g., without having to invest in a full 4x5 setup.
Thanks for any suggestions!
What is the reason to do this? Mamiya lenses too hard to find?
No, there are plenty lenses on the used market. I bought a 150mm (old type from the 1960s) on ebay, but the shutter is not working. I considered trying to repair it, but came to the conclusion I might as well try to upgrade both shutter and lens, if it is feasible.
I did a similar thing using a Graflex XL board. In an attempt to fabricate a more compact Camera.
HA! I'd like to say it's an ongoing project but the ongoing part seems to have lapsed due to lack of interest on my part.
Hmm... I considered Graflex XL lenses too. For now I managed to remove the retaining nut from the back of the lens using two screwdrivers. The Polaroid 600 SE repair manual suggest a special lens spanner, but fortunately it wasn't neccessary. The lens and shutter then falls out easily from the helicoid, just unscrew the PC-cord connector.
A few measurements of the 150mm helicoid - these are approximations, I just used some cheap calipers:
Minimum focal flange distance, from film to inner point of lense mount flange at infinity ~ 142 mm
Maximum focal flange distance, at closest focus distance of helicoid ~ 161mm
This can be adjusted with extension rings, which add about 20mm or 40mm each.
Outer diametre of back element of 150mm lens ~ 29mm
Diametre helicoid opening behind flange ~ 45 mm(guesstimate).
I just ordered a Schneider Xenar 150mm f5.6, as it should fit (as can be seen from the photos linked above). From the measurements it seems also e.g. a Schneider Symmar-S 150mm 5.6 should work, if my measurements are correct (back element outer diametre 40,5mm), however the APO Symmar will probably not (back element diametre 46mm). My goal is to achieve rangefinder focusing with the Xenar. I guess it should be possible by shimming the lens... I will let you know how it goes.
Here is the helicoid with the lens removed:
Last edited by dag.bb; 08-10-2014 at 05:33 AM. Click to view previous post history.
Reason: Added images
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