Hey, I just came across this little write up I did for modifying the I-69 for use on m43... you might find it useful. (Other links I've found were not helpful!)
Since there seems to be a lot of confusion regarding the modifications needed to make the Industar-69 compatible with a Micro 4/3 camera, I am providing these notes on how to do it. Unfortunately, I did not visually document the procedure when I modified my own lens because I didn’t realize that it would seem so complicated to others or be useful to anyone at the time.
But here are the steps I performed:
1) Loosen the three set screws in the focusing ring.
2) Lift out the focusing ring.
3) Unscrew the lens block from the lens mount.
4) Remove the focus limiting screws.
5) Sand or grind down the raised lip on the inside of the lens mount. (This is what prevents the lens block from retracting into the body enough to achieve infinity focus.)
6) When you think you have removed enough material – and you don’t need to remove that much – clean everything off, screw the lens block into the mount, attach the lens to the camera using an appropriate LTM adapter and check if the lens block will focus to infinity on the camera. If it doesn’t, remove, disassemble and remove more material from the lens mount until you get infinity focus. Note that you do not need to attach the focus ring at this point.
7) After you achieve infinity focus, disassemble, give everything a final cleaning, grease up the helicoid and screw the lens block into the mount and attach to the camera and replace the focus limiting screw (optional).
8) Focus the lens on an object out at “infinity.” In reality a few hundred feet is good enough – think distant telephone pole.
9) With the lens block focused at infinity, slip on the focus ring and line up the focus mark to the infinity mark. When you are convince the two are both set correctly, tighten the focus ring set screws. Note that for FSU lenses, these screws are made from inferior steel and you have to avoid over tightening or they will snap!
10) At this point the focus scale on the lens is calibrated for the lens when mounted on a Micro 4/3 camera and will achieve infinity focus, but due to a peculiarity of the I-69 lens design, the aperture mark will be off (the two are coupled by design and only correct when calibrated for a Chaika camera and even then the setting is suspect!).
11) To correct the aperture scale marking, open up the lens all the way and use a Sharpie to add a mark to the silver aperture ring in front of the f2.8 mark.
12) You now have an Industar-69 perfectly calibrated for your Micro 4/3 camera.
13) Enjoy!
