UV curing adhesive as a scratched lens repair?

Kino · Dec 30, 2019

Just wool-gathering here...

Was wondering if you had an abraded front lens element with very fine cleaning marks, enough to cause impact to image contrast, if very lightly coating this lens element with UV curing cement would help or hurt the situation?

Guess it depends on the refractive index of the lens glass Vs the cured cement and how evenly and thinly it could be applied...

What would be worse? The original light scattering of the scratches or the impact of the UV cement index mismatch?

What about a heavily abraded lens?

Opinions?

Nodda Duma · Dec 30, 2019

Biggest impact will be a change to surface irregularity (affecting wavefront error) and/or radius of curvature (affecting optical power). The result will be a hit to MTF and it doesn’t take much. It will be a more significant impact to final results than loss of contrast, plus the impact to the AR coating performance can also reduce contrast (via ghosting / double bounce path)

AgX · Dec 30, 2019

Much easier remedy with better result would be covering the scratch with black enamel/ink.

BradS · Dec 30, 2019

Or simply use a lens hood. Generally speaking, scratches on the front element don’t really matter that much. Singles get colored in with sharpie and over zealous cleaning gets guarded from the direct sun. Or, just enjoy the reduction in contrast.

Kino · Dec 30, 2019

Thanks everyone.

glbeas · Dec 30, 2019

That thought would be better directed at enlarger condensors that have wound up with scratches that show up in the image. If it matches the refractive index of the glass well enough it would probably eliminate the problem. Think about the stuff to repair windshield cracks, bet that would work.

AgX · Dec 30, 2019

The windscreen case is a bit different. The hole likely is bigger and there is much less requirement on the optics of the repair, but on the mechanics. The idea is to prevent a crack to form and to avoid marks on the wiper blade.
Why go and have the trouble of doing this all and even to fear for producing scratches in addition, if one just can black-out the issue?

Kino · Jan 25, 2020

Wow. Bad news on the Rolleiflex 3.5! Finally got a roll of Ektar 100 processed and I think this camera is going to be a shelf Queen. If the damage had been a little more even, it might be somehow justified as a portrait camera for vain old men and women, but the pattern is too irregular and blob-like.

Too bad, the body is in fairly good shape...

Dan Fromm · Jan 25, 2020

What, if anything, did you do to the lens?

Kino · Jan 25, 2020

Dan Fromm said:
What, if anything, did you do to the lens?

I just cleaned it as best I could.

Dan Fromm · Jan 25, 2020

Fill the scratches with india ink. This works for large deep scratches. Don't ask me how I know.

I've never tried it on a lens with many shallow scratches but if you want to use the camera its worth trying.

Kino · Jan 25, 2020

I have to wonder if I will have any image forming glass left over at all...

Nodda Duma · Jan 25, 2020

If I had the time, I’d be tempted to say send it to me and I’d polish the scratches out. But I don’t.

Maybe you’ll find another camera that has a bad body but a lens that you can salvage.

Kino · Jan 25, 2020

Nodda Duma said:
If I had the time, I’d be tempted to say send it to me and I’d polish the scratches out. But I don’t.

Maybe you’ll find another camera that has a bad body but a lens that you can salvage.

I thought that would ruin the geometry of the lens...

Sirius Glass · Jan 25, 2020

Heck, put it up for sale on eBay and use these words in the description:

rare
hard to find
highly sought after
minty

Nodda Duma · Jan 25, 2020

Kino said:
I thought that would ruin the geometry of the lens...

Only if you don’t know what you’re doing.

Kino · Jan 25, 2020

Sirius Glass said:
Heck, put it up for sale on eBay and use these words in the description:

rare
hard to find
highly sought after
minty

"Limited Super Soft Portrait Edition"...

Kino · Jan 25, 2020

Nodda Duma said:
Only if you don’t know what you’re doing.

I'll keep my eyes open for a donor body with both lenses intact, but those are getting very rare and dear. Too bad; look down into the corners of those images and you can catch the former glory that resided in the center of the lens...

ic-racer · Jan 26, 2020

Kino said:
I just cleaned it as best I could.

First roll through my Rolleicord was similar to those. I then did a second roll with only overcast lighting and it was, as expected, fine. With some work, however, I was able to disassemble the lens and clean all the lens surfaces. I was lucky with that one but I have also had many cases like yours where the lens appears to have permanent damage.
But you might want to see how it performs with low contrast scenes and small apertures prior to never using it again.

removedacct1 · Jan 26, 2020

Food for thought: this image was made with a Schneider 105mm f2.8 Xenotar lens I was given last year. The front element looks like it was cleaned with steel wool. Not all damaged lenses are junk.
From a wet plate collodion negative on 4x5 glass.

BradS · Jan 26, 2020

Kino said:
Wow. Bad news on the Rolleiflex 3.5! Finally got a roll of Ektar 100 processed and I think this camera is going to be a shelf Queen. If the damage had been a little more even, it might be somehow justified as a portrait camera for vain old men and women, but the pattern is too irregular and blob-like.

Too bad, the body is in fairly good shape...

View attachment 238835 View attachment 238836 View attachment 238837

Thanks for sharing these...pretty interesting results. I would not have guess that the effect would be as non-uniform as it is. Too bad...

BradS · Jan 26, 2020

Sirius Glass said:
Heck, put it up for sale on eBay and use these words in the description:

rare
hard to find
highly sought after
minty

or, my favorite...
"Scratches do not effect shooting"

Sirius Glass · Jan 26, 2020

BradS said:
or, my favorite...
"Scratches do not effect shooting"

A subtlety missed by most.

BradS · Jan 26, 2020

Sirius Glass said:
A subtlety missed by most.

indeed.

Dan Fromm · Jan 26, 2020

paulbarden said:
Food for thought: this image was made with a Schneider 105mm f2.8 Xenotar lens I was given last year. The front element looks like it was cleaned with steel wool. Not all damaged lenses are junk.
From a wet plate collodion negative on 4x5 glass.

Paul, its great that you got such nice results with y'r 105/2.8 Scratchotar. My 80/2.8 wasn't cleaned with steel wool, but with coarse sand paper. Totally unusable.

UV curing adhesive as a scratched lens repair?

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