What's the latest lens you repaired yourself?

[RokkorDoctor]

Intended as a sister-topic to the topic "What's the latest lens you added to your collection?" in the main forum.

A bit tongue-in-cheek perhaps, this one may not see much activity...

This topic is intended to note the (ideally successful) DIY service or repair of a lens, which may or may not already have been part of your collection.

It is not intended to highlight any specific service information or hints, for that a lens-specific dedicated topic would be more appropriate in order to facilitate better search-results.


Yesterday I gave a full CLA to a Minolta MC ROKKOR-PE 200mm f/4.5 lens bought for spares. Underneath all the dirt, dust & grime it turned out to be far too good to take apart for spares, so a full CLA it was. As usual for lenses of this age, the old grease had let go of all the oil and the helicoid was just sliding on a layer of dry lithium soap and molybdenum disulfide (still very smooth of course; this is a Minolta Rokkor after all ). No oil in the aperture mechanism, so I could leave that in situ. The glass was free of any scratches, fungus, or haze.
Fully cleaned and re-lubricated; all good now.

The day before that I (re-)serviced an older version of the same lens, an MC-I. I had already given that a full CLA several years before, but at the time incorrectly assessed that the aperture mechanism was clean (first time I made that mistake ). A few days ago I noticed there was in fact a trace of old oil in there, causing occasional sluggishness. So I cleaned the aperture assembly of that one.

Both lenses now in full working condition below, MC-I on the left, MC-X on the right):

[stevemark]

Konica AR 2.8/24mm - a rather nice looking sample, but with fungus. When I bought it for around CHF 40.-- i was aware of the fungus, but at the time I didn't bother cleaning it, since I already had another, clean AR 2.8/24mm.

A few days ago I started working - the construction of the AR lenses is different that that of the Minolta stuff indeed. The AR lenses have a few glued screws and threads, so one has to carefully un-glue them before they come off. Another funny thing was that the entire optical block including aperture can be easily separated from the focusing mechanism. Quite clever.

No back to my cleaning of the lens: For whatever reason it had fungus on nearly EVERY lens surface. Never seen anything like that before!! So I really had to dismantle EVERYTHING and clean all the eight lenses separately. Quite some work indeed! A detailed repair info will follow.

S

[cooltouch]

Sigma 600mm f/8 mirror. It had some dust and slight fogging on the interior that cleaned up nicely.

[RokkorDoctor]

[RokkorDoctor]

[visualopsins]

Last two: M42 Asahi Super-Multi-Coated TAKUMAR 1:2 / 35 -- the first was sold as parts. Dusted it off was all the "repair" necessary. The second was a bit more complicated having "a missing screw", well, 5 screws, were obtained from a donor lens with "stuck aperture". The third, now missing 5 screws, has been partially repaired -- camera side was knocked deforming the metal. Got it reformed and partially working, but now it is missing 5 screws. Looking for another donor, from past experience maybe endlessly looking for another donor. LOL Very very easy to work on -- modular construction, "encapsulated" front and rear optic blocks...

Knowing when to stop "repairing" is another learned skill -- repair sometimes proceeds quite a bit easier after a hiatus such as a good night's sleep.

The Flecktogon 1:2.8 / 35 helical needs re-greasing sometime -- I've had it apart several times, not quite to unscrewing the helical. Now I know the aperture linkage mechanics quite well, however, having disassembled/reassembled that far a few times...

[cooltouch]

[kansalliskala]

Pre-ai Nikkor 180 / 2.8. Stiff helicoid - that was interesting to get right.

[RokkorDoctor]

[RokkorDoctor]

[stevemark]

[visualopsins]

[RokkorDoctor]

Minolta MC TELE ROKKOR-QE 100mm f/3.5

Full CLA yesterday. Looks like this was a lens made up from other good parts; it needed quite a few adjustments. All good now

[55]

[RokkorDoctor]

[55]

[RokkorDoctor]

Minolta MC ROKKOR-PF 50mm f/2.

Aperture was stuck/slow. Full CLA, but couldn't disassemble the aperture assembly so was rinsed in isopropyl alcohol.

There is another post on how I did the CLA.

[vandergus]

Well, I recently took on quite the eBay adventure. I bought a Zeiss 35mm Flektogon that needed, uh, a little help. The seller assured that all the pieces were present, they were just unable to get everything back together. I've got a few lens rebuilds under my built by now so I thought I'd give it a shot.



This is the first Zeiss I've worked on and, I gotta say, I was not impressed. There were a lot of plastic parts where I'm used to seeing metal parts and the aperture was incredibly fiddly. It didn't have it's own self-contained assembly, like I've seen in Takumars and Minoltas. Instead, you have to assemble the blades and coupling rings directly into the body, then try to get the retaining ring in place without bumping or nudging anything out of place. This took...several attempts.

I also discovered that there actually was one piece missing. The spring that stopped down the aperture blades had gone missing at some point in the lens's life. Luckily, I've amassed a nice little stockpile of spare parts and had an adequately sized replacement spring.

I still want to regrease the helicoid since the focus is feeling a little dry but getting everything together and confirming that I actually have a functioning lens was a big relief. Finally got my Flek!

h

[RokkorDoctor]

[kiddo]

A handsome lens![/quote]

Yes, it's a nice lens. Pretty good performance too, considering its age. I'm sure some fellow members will correct me, but I suspect that this is one of the smallest 100mm lenses you can find (excl. bellows lenses).

My smallest one is a bbar early poor coatings version, smaller and lighter than topcor 58mm.
And surprisingly it's got very fine focus and mechanics, despite the low weight.

[RokkorDoctor]

[kiddo]

That's right , is the adaptall . To be honest , i didn't know the size of that Minolta neither , just thought about the mdII 2.5 version I've got ,and I've assumed they might have been close in size

[StuG]

My latest success is clearing fungus from a Pentax-A 50mm 1.7. It was quite easy and I think I did it within an hour.

I have made unsuccesful other attempts with other lenses, however I not have a lens rubber tool, so I will be successful again. I hope...

[cooltouch]

Ah, forgot about this thread. I have another successful lens cleaning/repair to report.

Some months ago, I bought a Canon 7s with 50mm f/1.2 from my neighbor, who had inherited it from his father. The camera is in great shape and everything works pretty much as it should. But the lens needed help.

The rear element had some brownish fogging and droplets on it that were on the interior of the glass. Ironically, to reach the interior surface of the rear element, one has to dismantle the lens from the front. Being a relatively simple design, this was not very difficult to do. It did not require that I separate the focusing helical, fortunately. The entire optical group came out, at which point I was able to separate the rear element. The residue on it resembled tar, more than lens thread lube. I wondered at that point if my neighbor's dad had been a smoker.

I used a solvent that is mostly acetone to clean the lens surface. I was careful not to get the solvent anywhere else but on the glass. It actually took a fair amount of scrubbing (with lens tissue, of course) to get all the residue off, but I was eventually successful.

Reassembly went as smoothly as disassembly.

The result is a lens with excellent cosmetics, but flawless glass. I'm glad it came out so well.

[RokkorDoctor]