100mm f/2 and 50mm f/1.2 Repair

ethics_gradient

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Today I got my early (and hopefully not premature!) graduation present to myself, a Canon 7s, 100mm f/2, and 50mm f/1.2 along with a few other odds and ends. Both of the lenses seem to have issues, but I got a decent deal on the package so I think I'd rather try and keep/repair them than send them back.

The 100mm is in beautiful shape, but RF patch does not align at infinity. Looking closely it may have been the victim of an unskilled repair-person: one of the three larger screws towards the rear of the barrel is phillips head, unlike the other two. I suppose another person's screw-up is a can of worms, but assuming they didn't mangle or lose anything, how feasible would it be to attempt the repair on my own?

The 50mm I may just send out, it has a pretty sticky aperture ring, light fungus on one of the internal elements (behind the aperture blades), and a bent front filter ring. I like a challenge, but it seems like the rear retaining ring doesn't want to budge, and I don't want to force the issue with my somewhat oversized spanner. I actually do have the tool to repair the filter ring too, but given that the front element bulges out I don't want to risk trying it on my own. I'd also like to get rid of the infinity lock, I'm guessing that's a fairly easy/standard modification?

Also, is there any trick to getting the cap off of the rangefinder alignment screw on the 7s? I bent a paperclip to use as a mini-spanner but it turned out to be too thick. I did a staple instead, but the darn thing still doesn't want to budge.
 
I use a pair of fine-tip needle nosed pliers for the adjustment cap for vertical alignment.

The sticky aperture ring is likely a gunky build-up under the ring. A little 99% Isopropyl alchohol took care of the same issue on my Canon 50/1.4.

The sticking retaining ring can be a problem- been there before. Heavy-durt spanner will usually work, if not a drop of ronsonol might. Best to send that one out as it is not a cheap lens, but once the optics module is out getting the rear optics module out of it is easy. Beware of coating and glass etching if left too long.

I should look for my pictures of making a Canon 50/1.2 out of two parts lenses. One of them was missing the rear optics. The other was modified for some bizarre use, did not have a front element, and also had the optics module welded in place. Dremel and four cutting disks.
 
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Thanks Brian! Those must be as close to actual needle tips as possible, I couldn't even get a normal-sized paperclip into the holes. I could get the tips of my swiss army knife scissors in, but it still doesn't seem to want to budge. May go pop in to a jewler's and see if they can give me a hand.

I think I've pretty much settled on sending the 50mm out, as much as a fun project as it looks like it might be. I'm going to shoot with it a bit tomorrow out of curiousity, I've shot with a fungus-tinged lens before with no noticable results (on digital, no less).

The 100mm I'm kind of resisting on, because it shouldn't be that hard. I haven't been able to find any info on disassembling it though, this thread is now showing up on the first page of Google results 😛
 
Sears Craftsman pliers, cannot remember how old. I've also bought pliers there made for placing the spread-apart and compression type retaining rings, and filed the ends down.
 
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