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What method did you use to locate and hold the rear element in your conversion? How much do you have shaved from the mirror in your 5D? Any other clearance issues within the mirror box? Is the aperture control as per nFD standard or the older standard?
I used the existing rear element assembly. I simply used a Dremel to cut that part out of the existing mount and then mounted that into the new mount. It basically fit perfectly inside a C/Y adapter after grinding off the internal flanges of the C/Y adapter. Using the existing assembly in this way allows for fine-tuning because the rear element is threaded into it. Turning the rear element in the threads allows about 1mm of adjustment. I have not found any evidence that the rear element needs to be placed precisely where it was in the original design. As long as it is "close enough" the results are spectacular, in my experience. I only made a "reasonable effort" to get the rear element in the ideal position. I didn't measure any of the stuff. I just stuck it all together and made sure the rear element was about 1-2mm beyond the EOS mount, which my shaved 5d mirror easily accommodated.
It is a breach-lock lens, so the aperture control is the old style. I needed to fabricate and install two parts in order to ensure aperture control throughout the focusing range. Hours and hours messing with tin snips and various gauges and types of sheet metal, but so worth the effort.
Edited on Jun 20, 2009 at 03:55 PM · View previous versions