[aberratedsoul]

Decided to try my luck on a wide Tak whose profile photo seemed a little...off. Delivered today with a bunch of misfit friends and, well, she's seen some rough times head-on. There might be some black paint missing on interior surfaces, as well. Miraculously, the barrel and rear element are in great shape. Aperture closes a little slowly, but closes nonetheless. Focus ring gives butter a run for its money.

Posting a picture of the front element, which appears to have some serious coating scratches. Images are very hazy, especially in the center. Pretty sure someone used their angle grinder to clean this front element.

Slow and wide, has seen hard times... - Album on Imgur

Anyone have advice to share regarding a repair? I've only tried a rocket blower, Zeiss cleaner, a PecPad, and a microfiber cloth. I'm thinking some polishing compound might need to happen. It'd remove the coating altogether, I imagine.

Anyway, happy to add a 20mm f/4.5 Super-Tak to the collection of a handful of 55s, a nice 50 and an ugly one, two disgruntled 200s, a very pretty 135, and a gorgeous 35.

Is it okay to use Imgur to share a picture? I'm new here, but have been lurking for a while as I rapidly accumulate way more vintage glass than I know what to do with. Thanks for your kind replies

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Last edited by aberratedsoul; 04-22-2023 at 11:57 PM.

[yucatanPentax]

Hello and Welcome to Pentax Forums!

I'm sure you'll find a lot of useful information and advice here, just as I've received over the years.

On your lens, well, I have never used polishing compound on a lens. I suppose if done very carefully and finely to avoid "distorting" the lens, maybe it would work, if the lens is still usable without the front coatings. I have quite old lenses which have minimal, if any, coating in the first place. They are usable in the right lighting conditions and with a good hood.

I wonder what happened to the lens? It looks like the front element fell perfectly face down onto sand covered cement... But the filter ring doesn't seem to show a lot of chips as one would expect.

Yes, you can post links to photos. Many do, especially to show a full resolution image when uploading would degrade it.

[aberratedsoul]

Thanks for the reply and welcome message. I'm excited to be here and to actually have something of my own worth discussing.

I also wonder what happened to this poor lens. It came in an eBay grab bag of 6 lenses and a 3x extender plus some mystery extras (turned out to be a Nikon N2000 body, Canon flash, and auxiliary lenses). Overall I feel like I got my money's worth, even with the scratches and fungus in the Yashinon.

Querying the internet some more has suggested toothpaste as a gentle abrasive. Before I try anything, I'm going to be good and sure it has a fairly good likelihood of working. A weird Takumar like this has a special place in my heart and I'd hate to kill it.

[Dartmoor Dave]

Wow, I bet that poor old Tak 20 has got some stories to tell. Please take some test shots with it before you start trying to polish out the marks -- a lens can take a heck of a lot of scratching up and still produce surprisingly good results. Of course flare will be an issue, but the old trick of filling the scratches with black paint might help. Although some of those marks look so big that the black paint itself might be visible at smaller apertures.

Edit: Ah, I've just reread your original post and you have taken some test shots but they were hazy in the centre. That's sad to hear about such a classic lens. Perhaps you might be able to find one with a trashed rear element but a good front one, then put the best bits of the two lenses together? I know from my own Tak 20 that it's an easy lens to work on.

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Last edited by Dartmoor Dave; 04-23-2023 at 02:14 AM.

[marcusBMG]

A neighbour of mine worked in the optical industry and has a polishing wheel and jewellers rouge, so I tried taking the haze off the secondary lens in a 400mm f6.3. The glass polished up nicely, but the IQ was still shot. You can try doing something similar, but IMO it is unlikely to be successful - lens will flare, iq will suffer.

[ramseybuckeye]

Looks as though it has actual sand on it also. I think I would take that element out and thoroughly clean it, there may be some fungus under there too which may cause your haze. Way back I used to run a copy center where I worked, we used a product called Brillionize on the glass and scanners, it would make it very smooth and stop friction so you would have less jams on high speed machines. One of maintenance guys would come in and use it on his glasses so dirt wouldn't stick. If nothing else works you might try something like that, it fills in small imperfections. I doubt it would work on that element, but it is not permanent and can be cleaned off.

Another thing nice to know would be if there were any other Taks that may actually use the same front element where you could borrow. Probably not, that would be too easy.

[c.a.m]

Anyone have advice to share regarding a repair?

Hi, welcome to Pentax Forums!

I've done a fair amount of research to determine what could be done with one of my lenses that has a mild abrasion on the front element. My conclusion is that polishing is not a DIY proposition. Without the proper tools and jigs, it's likely that the surface geometry would be altered sufficiently to seriously affect the lens's optical quality. Even with professional work, coatings will be abraded and the original geometry will be affected, albeit to a lesser degree.

On my lens, the scuff is apparent, but overall the lens works okay. Low contrast or mildly-hazy shots (at smaller apertures) can be mitigated with post-processing 'de-haze', 'clarity' or other settings. Sounds like your lens is worse for its wear.

- Craig

[UncleVanya]

“Bones, can you fix her?”
“She’s dead Jim…”

Yikes that’s a messy front element. I’d look for a broken lens with the front element intact for a future swap.

[Bob 256]

I think I would reclassify that lens as a special effects lens - diffusion class. As mentioned above, polishing could well introduce sleeks and optical issues as bad or worse than what exist. In any case, you would be losing any optical anti-reflection coating on the surface as you mentioned. A good optical polishing compound is Cerium Oxide used with a suitable polishing tool. Good luck with whatever you do - post some photos.

[aberratedsoul]

My best guess is the lens was used to document a violent sandstorm. Or a pyroclastic flow. I'm amazed at the roughness of the glass, but niceness of the rest of the lens. Could just be a classic case of using the wrong wipe too many times. As it is right now, the special effects are little too much for my liking. Reminds me of the time I was trying to photograph the northern lights and my front elements developed a layer of frost.

Thank you for the replies and thoughts. I'll take pictures of whatever I do. Right now I'm thinking toothpaste, although I should have rock polishing compound socked away somewhere in the garage. Sounds like I have little to lose as long as I'm careful with the rest of the lens.

[Wasp]

The Takumar 20mm must be ultra rare. Kinda sad to see it in this condition. Judging by the top dollar that the SMC Pentax M 20mm f/4 fetches these days, a mint Tak 20 must be worth serious money.

It would be interesting to see how image quality is affected. Can you post a photo taken with it?

[aberratedsoul]

The Takumar 20mm must be ultra rare. Kinda sad to see it in this condition. Judging by the top dollar that the SMC Pentax M 20mm f/4 fetches these days, a mint Tak 20 must be worth serious money.

It would be interesting to see how image quality is affected. Can you post a photo taken with it?

Certainly!

https://imgur.com/a/ZegbjAz

It seemed pretty rare in my cursory search, so that's why I wasn't shy about pulling the LBA trigger on this lot (it also came with a Tele Vivitar 135, which I love, and the Yashinon fifty f/1.9), even though I had a very reasonable suspicion it was going to be a little rough. I never fancied myself much of a gambler, but cheapish adaptable lenses, mirrorless cameras, and eBay architecture has brought out what seems to be my worst treasure-hunting traits.

But now I can make swirly bokeh! A lot of it. And it's just fun to spell and say A.Schacht.

[aberratedsoul]

Tried some toothpaste last night. Wanted Arm and Hammer, but all I had was Pepsodent. The person who said the restoration is probably beyond a DIY job is probably right. I succeeded at making things a little worse. Started with a much watered-down mixture, but after seeing nothing happen, decided to go with straight paste, with saliva to rehydrate because the sink was far away and I forgot to fill/bring a cup and okay fine I'm lazy. Finger pads and PecPads were used for application. I may have even licked it a time or two to get a better sense for the element's microtexture (and to see if any toothpaste residue remained, as I have a soft spot for wintergreen). And yes, I'm grateful no one happened to walk in on my endeavor during that delicate moment. There's already enough concern about how much I like my photography equipment and I don't need anyone drawing false conclusions. Anyway, it felt rough...not quite like frosted glass, but not-not unlike frosted glass. It's already unusable in my opinion, so I might graduate up to cerium oxide from my rock tumbling kit and see if there's any way to make a jig with my Dremel. Pretty cringey, huh? At least I'm probably learning something.

[Phil Martin]

Decided to try my luck on a wide Tak whose profile photo seemed a little...off. Delivered today with a bunch of misfit friends and, well, she's seen some rough times head-on. There might be some black paint missing on interior surfaces, as well. Miraculously, the barrel and rear element are in great shape. Aperture closes a little slowly, but closes nonetheless. Focus ring gives butter a run for its money.

Posting a picture of the front element, which appears to have some serious coating scratches. Images are very hazy, especially in the center. Pretty sure someone used their angle grinder to clean this front element.

Slow and wide, has seen hard times... - Album on Imgur

Anyone have advice to share regarding a repair? I've only tried a rocket blower, Zeiss cleaner, a PecPad, and a microfiber cloth. I'm thinking some polishing compound might need to happen. It'd remove the coating altogether, I imagine.

Anyway, happy to add a 20mm f/4.5 Super-Tak to the collection of a handful of 55s, a nice 50 and an ugly one, two disgruntled 200s, a very pretty 135, and a gorgeous 35.

Is it okay to use Imgur to share a picture? I'm new here, but have been lurking for a while as I rapidly accumulate way more vintage glass than I know what to do with. Thanks for your kind replies

Sometimes we just have to accept a write off, this lens is beyond repair.

[yucatanPentax]

I hope you've removed the front element from your lens before applying any liquids? As far gone as the front piece may be, the rest may be usable to someone, if you eventually decide to unload it. No need to degrade the rest or create fungus conditions inside.