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E Dinkla
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Senior Member
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Posts: 2,613
Re: Color Rikenon 35mm 2.8 fun lens with triangle aperture.
2
3D printed part, 39mm thread rings, inner diameter fits the lens lously, about 0.5mm play.
3D printed part Cone plate, about 3.5 mm thick, sanding the flat side till infinity is reached
You will know this LTM 39mm thread type of adapters to Sony FE. Two 39mm thread rings used, one to press the lens on to the cone plate, the next one to lock the total. Empty adapter next to it.
At the rear of the outer lens tube, made of brass, is a flat outwards "disc" originally for mounting, this is pressed between the flat side of the coneplate and the 39mm thread rings. Position of that "disc" for infinity is halfway the inside end of the chrome adapter ring. The cone is just there to give more light blocking, does not mount anything. Two 39mm thread rings in a deeper and simpler 39mm adapter might have done it too.
Tried it with an odd M42/C-mount dual adapter but that one was too short. Odd because the M42 does not represent the register distance for M42 lenses and if one would use extension tubes the C-mount opening would vignet the incoming light. Wonder what its purpose is other than mounting C-mount lenses.
More interesting conversion part for a Canonet 45mm 1.9 lens, waiting for my Chinese reverse filter thread to Sony EF adapter plates to finish it further.
At some point I will put 3D data and pictures on a site to download. Mamiya Sekor CS, Minolta MD to EF too but that involves lathe work.
Met vriendelijke groet, Ernst
750+ inkjet paper white spectral plots: OBA content etc.
http://www.pigment-print.com/spectralplots/spectrumviz_1.htm