Need advice on two Nikon 80-200mm f:4.5-5.6 to make one lens.

I recently picked up an 80-200 lens that had a broken lens mount (plastic). When I got it the glass looked pretty good but with the the broken lens mount I was unable to test the lens with a camera. I looked for another 80-200 and found one with fungus under the front element and this lens looked pretty good as well and when I tested it with my D600 it worked well, auto focused and the aperture was snappy, so except for the fungus, which is not terrible it appears to be a good lens.

My dilemma is which lens should I make whole? The lens with the broken mount would probably be easier to fix if I just swap out the lens mount, but because it was obviously hit pretty hard to break the lens mount so it may have messed with optical alignment. The lens with the fungus would have to have the front element replaced and that job would be more difficult.

What would you do with these lenses?

There were a number of Nikon 80-200 lenses. I had an AI 80-200 with two bad elements and bought another pre-AI to swap elements. What happened is that the pre-AI lens was easier to repair and add an AI ring. So I never did swap the elements.

Thanks for responding, I appreciate your detailed posts on lens and camera repair. This forum is such a great source of info and has gotten me started in lens repair.

Normally I am against lens snobbery, but the Nikon 80-200/4.5-5.6 AF is one of the cheapest humblest lenses they marketed or made. That doesn't mean it's bad, I just wouldn't spend a lot of effort on thinking about which one to fix. Whatever is the least effort. If you swap the lens mounts and it's not much effort, if the one with broken lens mount turns out to be misaligned and make bad images, swap the mounts back.

It is a completely different lens from the older 80-200/4.5 manual focus lens (which is a pretty good lens, but never came in an AF version), so experience with that doesn't carry over.

Working on zoom lenses can be difficult. I repaired one Nikon 70-210/4-5.6 AF (slow, but not a bad lens), but tore the flex connector for the AF/electronic contacts, so it wouldn't AF or communicate electronically. Eventually, IIRC, I got another one that had some problem with the AF screwdriver and was able to combine parts to make them into one working AF and one MF lens.

I solved my problem and decided to use the lens with the fungus and proceeded to take the front element out of the broken lens mount lens. It came out very easily so I took the front element out with the fungus and tried cleaning it. I started with some lens cleaning fluid first and it cleaned right up, so I don't think it was fungus. I now have a nicely working 80-200 lens and spare parts and especially spare screws

BTW, Ken Rockwell is pretty high on this cheap plastic lens. He liked the small size and surprisingly good image quality.

Sounds like the fungus doesn't impact the lens performance (which isn't uncommon) so why not just use it as is.