Upload & Sell: On
Jim, I just finished converting one of each of MC Rokkor-X 85 f1.7, the FD85/1.8 SSC, and the Minolta 85/2.0. They are all great and each have something unique to their drawing style. The rear element retention ring on the FD85 SSC has to be cut down to clear a stock 5D mirror.
I have developed a "non-machining" method for nFD lense conversion. I found that the 50mm f1.2, 50mm f1.4, 135mm f2 and the 100mm f2.8 have essentially identical mounting configurations. I have developed precise templates and spacers in AutoCAD and get them reproduced on a laser sign cutting machine. The screw template is laid on the back of an M42 to EOS adapter and its elliptical hole is aligned with the corresponding adapter locking pin hole. Then a marker is used to mark screw position for exact placement and concentric positioning so that the lens is positioned correctly to the camera and the adapter holes line up exactly with the stock mounting holes (3 or 4 depending on the lens). The adapter spacer is made of the same rigid, durable plastic sign stock and has holes that align with the screw holes but in a mirrored orientation to the screw template. The thickness of the spacer is 1.33mm and puts the lens well within the infinity stop positioning range. Usually it is only necessary to back it off a few millimeters when tuning to infinity. Using this method, I converted three nFD lenses in about 2hrs (many hours went into the template development) once the initial design was developed. The spacer is black plastic and the laser cutting process gives the outer diameter the same kind of knurled look as the EOS adapter. As the outer diameter is exactly the same diameter as the EOS adapter it gives a very nice finished look.
The time to convert is mostly that which is required to gain aperture control (I have developed a couple of quick, reliable steps there too), convert the stock holes to M2 and to drill and countersink the holes in the EOS adapter.
I have also developed similar screw positioning templates for the FD SSC series, FL series as well as for the Minolta 50mm f1.2. I plan to develop more to cover the Rokkor series.
Lots of 85-90 possibilites here for me to consider, as I'm not going to regrind my brand new 5D mirror for just one lens. Thought about the 'lux 80, Rokkor 85, converting the FD85/1.8, even the minolta 85/2.0. APO R90 cron is too expensive.
One of my first lens conversions was the FD 17mm. I think the digital sensors were too much for it in the corners.
BTW, since I'm not going forward with another short mirror mod, this perfectly converted FD50L, I have just finished, will be for sale, if anyone is interested.