Hey guys, thought you might be interested in a slight modification that I made a couple weeks ago. I acquired this lens along with an ME-F body in hopes of having a little fun with the ancient autofocus mechanism when these two are coupled. However, upon inspection, the ME-F had a horrible case of corrosion, batteries had etched away the traces on the circuit board connecting power to the system (I could get it to power up if I directly connected 6V in the correct location, so the camera still worked fine, just bad contacts).
So I decided to have a little fun with this awesome fast lens, which really does produce very nice images when compared against similar zooms (I'm thinking the SMC Pentax-A 35-70/4, which is very good in it's own right).
So out came the tools. About an hours later, out came a new lens!
I completely disassembled the lens, removed all of the autofocus mechanism & wiring. I added some grease to the helical to achieve a damped manual focus action. After reassembly of the lens and verifying that it still worked, I pulled out the trusty dremel to remove the metal mount that supported the AF motor and battery compartment. I made sure to tape off any spots where metal shaving would try and sneak into the lens--I think I did a good job and avoiding anything getting in while I was hacking. I also re-cut the rubber grip so that it would sort of fit on the newly designed lens.
Now I've got a reasonably sized and decent looking 35-70/2.8. The MF is still somewhat difficult since the focusing ring is so small. But the focus action is pretty nice now that I greased it up, and it isn't too difficult to achieve the right focus, even with the small 1/4 turn travel of the focus. My main complaint about this lens is the ~4-ft min focus distance, so you can't really do any close-ups with this lens. But other than that it's nice, and it has the beautiful red coating that is unique to this lens (or so I hear).
Here are some shots of the modified lens: