Reviving lens marred by fungus or scratches.

Rolleiflexible · May 24, 2013

I'm wondering whether it is possible to repair the surface of a lens
that has been scored by fungus, or scratched, to minimize flare
when using the lens. I have a 75/4,5 Triotar in an Art Deco Rolleicord
that had fungus -- the fungus was cleaned and the lens looks clear
but it is a flare monster. From other photos I've seen online taken
through a Triotar, it shouldn't be so flare-prone as mine, and so I
am assuming that fungus and scratches have left the lens surface
in a condition that causes the flare.

So: Possible? And if possible, who (in the US) does it?

Many thanks in advance for your thoughts.

Sanders McNew

Jon Shiu · May 24, 2013

I haven't done it, but in my research the following source showed up:
http://www.focalpointlens.com/fp_intro.html

Jon

michaelbsc · May 24, 2013

If you can see the flaw, like a pit or scratch, then you can obliterate that portion of the lens with something like India Ink.

Obviously this also reduces the overall light transmission of the lens, and clearly isn't suitable if there is a substantial portion of the surface damage.

But if the spots are limited this ought to work fine. It's essentially going to cost you a partial stop.

Now, if the coating is gone and it just flares like an old fashion inflated triplet then I suggest you look for the old creamy dreamy look and save your money.

E. von Hoegh · May 25, 2013

Rolleiflexible said:
I'm wondering whether it is possible to repair the surface of a lens
that has been scored by fungus, or scratched, to minimize flare
when using the lens. I have a 75/4,5 Triotar in an Art Deco Rolleicord
that had fungus -- the fungus was cleaned and the lens looks clear
but it is a flare monster. From other photos I've seen online taken
through a Triotar, it shouldn't be so flare-prone as mine, and so I
am assuming that fungus and scratches have left the lens surface
in a condition that causes the flare.

So: Possible? And if possible, who (in the US) does it?

Many thanks in advance for your thoughts.

Sanders McNew

If the lens flares, it's probable that any coating was either destroyed by the fungus, or removed by whatever process was used to remove the fungus. Thake the lens and shine a penlight thorough it, is there a haze or fine scratches covering the surfaces? Haze can be cleaned, but fine scratches will cause flare and loss of contrast and there's nothing you can do except use a lens shade.

Rolleiflexible · May 25, 2013

Jon Shiu said:
I haven't done it, but in my research the following source showed up:
http://www.focalpointlens.com/fp_intro.html

Jon

Jon, that's what I was looking for, thanks. To the other responders,
a Triotar from an Art Deco Rolleicord is a 1930s-vintage lens -- it's
an uncoated lens. A lens hood doesn't do the trick. I'm thinking
that Focal Point may be able to resurface the lens. Or maybe I'll
luck out and find an old Rolleicord with a Triotar I can cannibalize
for the camera.

Sanders

E. von Hoegh · May 25, 2013

Rolleiflexible said:
Jon, that's what I was looking for, thanks. To the other responders,
a Triotar from an Art Deco Rolleicord is a 1930s-vintage lens -- it's
an uncoated lens. A lens hood doesn't do the trick. I'm thinking
that Focal Point may be able to resurface the lens. Or maybe I'll
luck out and find an old Rolleicord with a Triotar I can cannibalize
for the camera.

Sanders

The service Focal Point advertises is for repairing the coatings. Repolishing a lens with scratches is not really feasible, as removing the glass neccesary to eliminate scratches changes the formula of the lens. Also, it's expensive.

Gerald C Koch · May 25, 2013

Fungus damage can be removed by using cerium oxide mixed with water as a polish. People make telescope mirrors all the time and the final step is polishing. Check the web for suppliers. As mentioned above the coating will have to be re-applied. When I was in graduate school I had to polish sodium chloride optical windows all the time. Only difference was using ethyl alcohol instead of water. (Sodium chloride transmits infra-red light while glass will not.)

sangetsu · Jun 17, 2013

I have been able to remove light fungus and marks using toothpaste and a damp cotton swab. So long as the glass isn't etched by the fungus, toothpaste should be able to clean things up. If you are cleaning the inside surfaces, scrub lightly in a circular motion, and take care not to damage the coating.

johnielvis · Jun 17, 2013

if it looks clean, then you're better off $elling it to a $ucker and buying a good one. Lens polishing/grinding is always more expensive than getting a new lens in most cases.

try the toothpaste trick first, though, you have nothing to lose. Sounds like it'll work--never tried it but...sounds promising, particularly if you have nothing to lose.

Truzi · Jun 17, 2013

Be careful. Some toothbrushes have abrasives that can harm your lens further. When I was a child I used Ultrabright toothpaste to "brush" the paint off a toy car (an Hot Wheel).

David Lyga · Jun 18, 2013

I have found that household ammonia cleans quite a bit of fungus off the lens. That and keeping the glass in bright sunshine for extended periods of time both help to attenuate that scourge. As far as the scratches go, BIG scratches best be filled with opaque material as michaelbsc has suggested (#3). - David Lyga

Fixcinater · Jun 18, 2013

I have recently acquired a Sonnar 150mm for Hasselblad, which looks like it was dunked in the ocean, so perfect for doing some real-world testing. Lots of cleaning marks on the front element, and toothpaste didn't do anything to the ruined coating. I then tried aluminum polish which cleaned it up. I haven't done testing yet but it looks markedly better and much more reflective than it once was.

Mark Feldstein · Jun 22, 2013

Possible? I don't know. If it requires recoating I think you'd be better off avoiding situations that produce flare and get a good lens shade. OTOH, if it residual cleaning material and it needs some sort of disassembly, recleaning and polishing, you could try these guys at Midwest Camera. They give online estimates that are pretty reasonable.
http://www.midwestcamera.com/classic.html

Also, since you're in NYC, NY Lens and Repro merged with Calumet. NYLR always did great repair work and since they're in with Calumet now, take a ride down there and ask them to take a look. Calumet Photographic at 22 W 22 Street, NYC. It might be worth having them check it out.

Newt_on_Swings · Jun 22, 2013

I went at a front element the other day with toothpaste (the plain white type ) together with hydrogen peroxide and methanol to prevent it from drying out. Went at it for half an hour and it didn't do squat. I'll have to try some other polish.

Ian Grant · Jun 22, 2013

Gerald C Koch said:
Fungus damage can be removed by using cerium oxide mixed with water as a polish. People make telescope mirrors all the time and the final step is polishing. Check the web for suppliers. As mentioned above the coating will have to be re-applied. When I was in graduate school I had to polish sodium chloride optical windows all the time. Only difference was using ethyl alcohol instead of water. (Sodium chloride transmits infra-red light while glass will not.)

I bought some Cerium Oxide last year when i bought new stocks of polishing grits. I had to make some Rollei focus screens for a Microcord & Rolleicord III and decided to give the Cerium Oxide a try after the #600 grit I normally use - the reults were the glss began to polish smooth losing the ground grain. The Lapidiary supplier I use had told me they mainly sold Cerium Oxide to telescope makers.

Ian

E. von Hoegh · Jun 22, 2013

All you guys using abrasives like cerium are taking the glasses out of the cell and using pitch blocks to polish them, right? Because if you don't, you'll spoil the figure of the surface and have a nice shiny paperweight.
There's a reason it's expensive to get lenses repolished, it takes skill and special tooling made specifically for each job.

Reviving lens marred by fungus or scratches.

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