There ought to be enough accumulative photographic knowledge amongst members of this esteemed forum to solve my problem. Well, hare's hoping anyway. Problem...To fit a Canon FD lens onto a bellows that has a Pentax M42 x 1 female thread. The manual aperture ring on the lens must function but data is not fed to the M42 thread. The obvious answer is to use a FD to M42 adaptor.....very difficult. According to the Pentax forum such an adaptor has never been commercially produced, if my memory serves, it's to do with the back-focus or some such. http://photo.net/canon-fd-camera-forum/00XDcp A few special adaptors may have been made to order by someone like Novaflex. I have done it on paper using four items, but it is far from ideal. I have used two adaptors, a step-up ring and a male to male coupler. The step-up ring is M42 x 1 and one of the adaptors is M42 x 0.75, they 'would' fit together with effort, but as I said 'far from ideal' If you offer any solutions can I please ask that the adaptors are 'available' not theoretical, and not from ebay.
This begs the question: wouldn't it be a LOT simpler just to either use an M42 lens or to acquire an Canon FD bellows? Seems like that would be a lot simpler (and potentially cheaper) than cobbling together a Rube Goldberg solution. It makes sense to me that a commercial CanonFD-to-Pentax M42 adapter is available since Canon FD has a shorter lens register than M42 focus in normal operation would be difficult to achieve. Obviously for macro use, that's not necessarily an issue, but that's the reason such a beast is going to be difficult to find.
Someone's been posting this week about using 3-D CAD software to merge 2 adapters together and 3-D print them. (sorry it's theoretical, but should be practical.) However, I don't know enough about the FD aperture control to say what is needed for that. Barry
Well, I'm sure there are other combinations that would work, but this was the first I could find: FD lens to Nikon F mount adapter: http://www.amazon.com/XCSOURCE®-Adapter-Canon-Nikon-Mount/dp/B00BJG6O90 Plus a Nikon F lens to M42 mount adapter: http://www.amazon.com/Pixco-Adapter-Macro-Camera-camera/dp/B00B2KF67Y Keeping the whole lot together could be a challenge, and for that perhaps you need this: http://www.amazon.com/Gorilla-7805001-15g-Super-Glue/dp/B001IY82FM
Just thought of another really cool 3D printer item that would be cool. Custom extension tubes + adapter.
I'm the one that is getting a 3d printed custom adapter. I developed a model for Agfa Ambi Silette lenses to mft. It really didn't take very long to create the model. I found on the Thingiverse website an Ambi Silette to Leica mount and a Pentax k to mft adapter. Using the free, browser based site Tinkercad I was able to lop off the unneeded ends and combine the pieces to make my adapter. The hardest part was getting as accurate registration distance as possible. I have no expectations that it will be perfect, but hopefully good enough. I ordered my adapter from the site Shapeways. I was just notified this evening that the part made it past their proofing process. They are going ahead with the print. M42 threads may be a little more tricky. I have my doubts that 3d printing is good enough to get really accurate machine threads. It may be worth a shot, though. My adapter took a few hours to create and about $30 to get printed and shipped. If you want to look into this, I would be happy to share my experience. Also, if mine works, there will be some pictures taken with the Ambi Silette lenses on an E-M10 here in a couple weeks.
Since respect for mount distance is irrelevant at this point, just buy an fd adapter and a m42 adapter and rig them together some way that blocks any light gaps.
