Any success in re-coating Canon 50/1.8?

[Fixcinater]

I recently picked up a cheap late, black Canon LTM 50mm f/1.8 lens that had a haze problem from a seller in Japan. Wasn't big money and he included some sample images with the listing so I knew it wasn't *too* wretched.

It's exactly as described so I'm happy with the transaction but it has made me curious:

Has anyone sent in a hazy element to one of the re-coating services even with the etched surface which seems to be the common result on these Canons? I've seen plenty of examples of front elements with scratches/cleaning marks saved by this service but haven't seen any proof of repair on etched surfaces.

It may not be the best financially compared to buying one that doesn't have the issue but if the rest of the lens is mint, why not "save" it from the shelf?

Thoughts/experiences?

 

[Dante_Stella]

I'd say it's absolutely not worth it on one of these lenses. If it doesn't clean up, and you can't live with it, buy a new one. Re-coating is about a $250, 6-12 month operation.

If it's haze in the cement, it's worse.

But the good news is that on the many Canon lenses I've owned from that era, haze was universally vaporized oil and not something worse.

Dante

 

[View Range]

Why do you think the lens needs re-coating? As Dante says haze is usually on the surface of interior glass and usually is easily cleaned after disassembly. Often partial disassembly is enough to get to the hazed surface. Also re-coating does not remove scratches, assuming the scratch is in the glass.

 

[Vince Lupo]

Don't know if this would be appropriate for your lens , but I just tried this with my Xenon lens: http://www.rangefinderforum.com/forums/showthread.php?t=148430

 

[Fixcinater]

Thanks for the quick replies:

I've cleaned out the oil deposit haze on my Canon LTM 50/1.2 which was entirely different, this is etched coating to be sure.

I've disassembled down to the surface, tried Simichrome polish on it with very little improvement...something a bit more aggressive will be next in line for this copy.

I guess part of my curiosity is whether an old lens design like this, or any of the other Canons, or say a Summarit 1.5 would be further improved, even compared to when they were new, with modern coating.

 

[kuuan]

Fixcinator I wish you best success in repairing the etched glass! Please, if success or even failure, be so kind and report back to tell us your experience.
I have various Canon LTMs that have etched glass that definitely can't just easily be cleaned off. I had manually tried to polish their surface with a variety of metal polishers but so far with very little success. Most frequently effected lenses, to a point that it is difficult to get a clean one, seem to be the 1.8/50 and 3.5/100.

 

[nhchen]

A few years ago I polished out some serious etched glass on my canon 50/1.2. I used cerium oxide and it took quite a few hours(!) before I saw any difference. Think I watched a movie on TV while doing it. I know it wasn't the proper way to do it and will never be as good as when it was new, but now at least it is useable again. The weird thing is that the lens still fogs up on that exact same surface every few months, but that can be easily wiped off.

Regards,
nathan

 

[kuuan]

thank's a lot for this Nathan. Cerium oxide it is, best sources keep on recommending it.
( I am living out from a suitcase around Asia most of the year. That's the reason why I have not bought and tried Cerium Oxide yet, nor something like a Dremel. )
Where best to get Cerium Oxide, any suggestions? What jewelers use to polish, would that be the same?

 

[nhchen]

I just got some off ebay, found the smallest amount possible. It was ~$10 I think. I did it by hand so a dremel would definitely be faster.

nathan

 

[kuuan]

thank's once more Nathan, just bought some off ebay ( my problem right now is where to ship to, but no big loss in case I won't get it, is was less than 5 usd incl. shipping )

 

[Fixcinater]

OK, made some progress:

Tried another chrome polish with no change in results
Tried Turtle Wax automobile paint polishing compound with no change in results
Tried Dremel brand's red polishing compound that they supply with their polishing kit. That started making moves. Somewhat more aggressive than I would like it to be, but at least it's moving faster now.

Will need to carefully monitor progress as I get down to the bare glass. Took some before shots and will follow up with afters once I've gotten it to where I am happy.

 

[kuuan]

thank you very much Fixcinater for your report! Hope you will have even more success and report again 🙂

OK, made some progress:
...Tried Dremel brand's red polishing compound that they supply with their polishing kit. That started making moves. Somewhat more aggressive than I would like it to be, but at least it's moving faster now...

could that be 'Ferric oxide', also known as "jeweler's rouge"? :http://en.wikipedia.org/wiki/Iron(III)_oxide#Polishing
in the wiki article it says, quote: "Rouge cuts more slowly than some modern polishes, such as cerium(IV) oxide, but is still used in optics fabrication and by jewelers for the superior finish it can produce"

 

[furcafe]

In theory, there might be some improvement under ideal conditions (lens is re-collimated to adjust for lost glass, etc.). However, there are some problems: (1) I doubt that shops that do re-coating will be able to match the standards & materials of truly modern factory-applied coating (e.g., only single-coating, not multi-coating); (2) a substantial amount of improvement seen in modern lenses is from improved glass & re-coating obviously can't improve that situation; & (3) plenty of those old lens designs were brought into the modern era (you just have to do the research) so you're not really gaining much by updating an old, commonly-found, vintage lens.

I guess part of my curiosity is whether an old lens design like this, or any of the other Canons, or say a Summarit 1.5 would be further improved, even compared to when they were new, with modern coating.

 

[Fixcinater]

Thanks again for the most recent thoughts, they are encouraging and I'm glad to hear about the fact that the independent shops are only single coating, it lessens my desire to refurb completely.

Here's what it looked like before I did much of anything. Will post again once I've got the coating gone.

 

[Frontman]

Whatever you do, don't use a Dremel tool and polishing wheel to try to polish off the haze, the glass will become pitted. The best way to remove the haze is with cerium oxide paste, and a pencil eraser, the kind attached to the end of a regular pencil. Be prepared to spend a couple hours at least.

 

[newfilm]

Fixcinater, I also have a canon LTM lens that has haze surface that wont go away, I've tried tooth paste + dremel + q-tip for an hours nothing seems to change.

I dont have the dremel's polishing compound, but before I run to get some I wonder how was the final result after this few months?

 

[Fixcinater]

No change in result, still have some deep pits that likely will not go away. Maybe yours will not be as bad as mine so would clean up better. I'll likely keep working on it in my spare time until I feel up to testing it and see what the images actually look like.

The Dremel polishing compound is what I would probably call an intermediate polish so it works faster (remember, any polishing compound is working by scratching the surface of whatever you apply it to) so is good for my application for now but will definitely reduce overall contrast by applying those scratches all over the surface of the glass. Therefore, before I test it, I will polish it again with a finer compound and get more contrast back from reducing the scattered light. The chrome/billet aluminum polish I mentioned earlier in this thread seems to work well for that "final" polish. Both the Mother's Billet Aluminum polish and the Happich Simichrome polish seem to do well in that application, with the Simichrome taking off coating very efficiently.

Hopefully that all makes sense, it's been a long day cheering on Froome and the peloton in the Tour de France by way of delayed web TV coverage.

 

[Fixcinater]

As for the toothpaste, it did not seem to do much for my lens. I got better, faster results with the Mother's and Simichrome.