Mamiya 7 lens – call to repairman

Discussion in 'Medium Format' started by alpshiker, May 16, 2017.

  1. I have this seemingly excellent 210 N f8 that I wish to use on a shift-stitch device for landscape. This will require to alter the lens by removing the shutter blades or preventing that they can close, and to build a special adapter because the FF distance of the Mamiya 7 is some 3,5 mm shorter than the standard M645 mount. Or maybe machine the lens mount, or graft the lens elements in another lens like the plain 210mm for 645, if any of that is possible with a reasonable expense of work. But before anything is attempted that will destroy the lens as far as it's initial use is concerned, I wish I could check if the lens image circle will fit within the shift device, because this lens has a special design with small front and a large rear element.

    Is there any way to open the shutter by an electrical means so that it will stay open? I don't want to test before I know what I am doing. I noticed on the wiring diagram that there are two contacts for magnets, one is for the open position and another one for the closed position. This is probably for the B pose. But there are also other contacts for shutter control. Well, I suspect that what I am asking won't work if the lens is not coupled to the camera, but maybe there is a repairman trick to open the lens to see through it for inspection or bench calibration? And if all of that is impossible anyway, it is always interesting to talk about it.
     
  2. It would help if you were to clarify which mount you wish to adapt what lens to. Sounds like you want to go from a Mamiya 7 lens to a Mamiya 645 body mount, but that's not clear.

    Why not start with a lens that has a known large image-circle, and one that can easily be modified? Something like an LF 210mm f/5.6 Symmar or Sironar. Or even a shutterless 210mm f/4 Mamiya-Sekor for M645.

    LF lenses and barrel-mounted copying lenses can be got dirt cheap these days.
     
  3. Hi Joe,
    Yes I know, there are easier ways. The reason I am considering that lens is that I can make use of a 90mm image circle. The Mamiya 645 lenses have 75mm. I also want the sharpness and contrast that ULD lenses produce on distant subjects, like mountains. The 210 f4 is probably a little too weak, although I only read other's comments. The AF 210 ULD would be fine, given a smaller image circle, but as you know, it has no manual aperture ring. The 200mm lens I use now is a Pentax 67. It is pretty sharp, but sometimes subject to flare in the centre. And talking LF lenses, I have tested my Fujinon A 240mm f9 on the device. It has reasonably good sharpness, and of course a huge image circle, but the distance of the back pupil towards the throat of the lens mount gives way to a lot of vignetting. That would be where the M7 lens could be far superior. Is is also a very compact and lightweight lens, and certainly flare resistant. Anyway, I'm just weighing the possibilities.
     

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