Help on lens RF accuracy repair?

[ChipShorter]

So I got a fat elmarit 90 f2.8 from the bay. It seems to focus accurately in close (up to about 6 feet), but farther than that and the focus is wrong. Even infinity isn't properly focussed, even at smaller apertures. I've sent an email to DAG about getting this fixed, but as this is a cheapo lens, I thought I might see about fixing it myself.

Anyone know of a good resource for this kind of a fix? books, websites, etc, on what would have to be done?

Thanks!

 

[kzphoto]

I would think the sloped cam isn't in the right position for the lens. Most likely the optics were removed and put back into the lens, but on the wrong threading.

If you're comfortable with disassembly, you could pull out the optical block, and try to re-insert the block into the focusing helicoid. You may have to rotate the helicoid and the optical block a few times to get the right placement, but it shouldn't take more than an hour or so.

At least that is my guess! I haven't worked on these lenses, but if it's similar to other Leica lenses, you'll be fine.