Luminous Landscape Forum
Equipment & Techniques => Medium Format / Film / Digital Backs – and Large Sensor Photography => Topic started by: rastas on December 04, 2012, 11:29:29 pm
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After exhaustively searching the internet, I found one obscure reference to someone who modified a dsLR shift lens so it would work on a mamiya 645 camera with a digital back attached. They did this by cutting away the shift part and adding a mamiya mount to the lens at the correct flange distance. Even with this though, it seems like the lens elements get in the way of the mirror. Has anyone ever heard of this or actually done it?
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Hello Rastas,
I would recommend the Hartblei 45mm lens than modifying a dslr lens.
http://www.hartblei.com/lenses/lens_45mm.htm
Cheers
Simon
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Yes one can do such "crazy" things. 135 shift lenses cover roughly the image circle of 645 format. So one can either use them directly on a Hartblei HCam or an Alpa FPS cam or one has to shorten the back of the lens by machining away the shift mechanism in order to adapt the too short 135 flange distance to the longer 645 register. I did this with a Schneider 28f2.8 PC lens and added a Contax 645 mount from a disassembled C645 distance ring (now the connecting ring is black anodised to avoid reflection). Works fine with mirror lock up (by a tooth stick;-). Enclosed a sample pic with Contax 645 cam and Leaf Aptus-II 7 33 MPixel 48x32 mm back.
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Simon.... I want a wide lens solution for my 645 camera, and that lands you mentioned is not it. Chris! This is a text Lee what I was looking for. Thank you for sending this information. On the mamiya 645,the mirror up only seems to work when there is a mamiya lens attached to camera, so I have to find a way around this. Is that 28mm you modified giving you super wide coverage?
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This weekend I did some shots with the combination Schneider 28f2.8 PC (Contax 645 converted) + Contax 645 cam + Phase One P65+ back. Enclosed a full frame shot (at f16 or f19) which shows the vignetting outside an image circle of about 62mm (the 54x40mm back would require 67mm). Slightly cropped you still get a 50 MP file at about 19mm equivalent 135 focal length with reasonable edge/corner sharpness. Also no (or very little) color cast towards the corners within the 62mm.
Theoretically one also could use Pentax or Nikon 28f2.8 PC lenses and shorten the back to add a 645 mount, but the Schneider lens is in particular suitable for this modification because the focus ring and the aperture ring sit quite in front of the lens, so cutting the back 22-25mm of the lens just take away the shift mechanism.
One pic shows the little black tube I stick in the mirror box to hold up the mirror to avoid interference with the back barrel of the lens. For that lens obviously a back with live view would be very useful:-)