I have purchased over the years, a large number of old lenses. Many of those lenses have been in poor condition. So, I have been concerned with rejuvenating lenses for some time. I’m reminded particularly of a Schneider 360-millimeter f5.6 lens and a Rollieflex f2.8 that were improved by different techniques. The Schneider had several distinct scratches which affected its performance. As you might imagine this lens had a large front element. I used black water-based paint to fill the scratches. The black paint was on a very small percentage of the front element of the lens so it did not affect the image, however stray light from the scratches did affect the image. The light from the scratches could cause overall flare, which affects shadows and perceived sharpness. Also, the scratches could sometimes cause visible image flare when light hit them, which was bad. I would certainly use this technique again on a lens that had distinct scratches, particularly if there were only a few. The Rollieflex was another matter, the entire front element of the lens had scratches, mostly very small ones. This was some time ago, and there was a business in Pasadena CA. that would polish and coat lenses. I believe the name was Pacific Optical. Anyway, that was a very effective treatment for that lens. I also had them coat an old Schneider Angulon, 165mm, that I used for many years, which did improve that lens.
I do not know of any company that is polishing camera lenses at this time. I wish I did. I do understand that some opticians now have lens coating facilities in house, so, perhaps it would be good to find out if this is a way to improve old lenses. Regardless, I wish I knew of a company which would polish lenses with precision.
I was searching for information about restoring lenses recently, because of a lens I recently purchased which has a good deal of scratching. There was some information about physically polishing scratches out of lenses, but I believe this is unlikely to work. If you polish only part of a lens, you will damage any coating on that part of the lens and change its optical character.
There were also suggestions about coating lenses with auto wax products. I thought that this might work, and it was certainly worth trying. This is the manner in which I tested the idea. I took a UV filter and damaged it with 400 grit sand paper. This can make an interesting optical effect, but regardless it really does damage the filter. I then tried various products on the lens and some of them did improve the lens in a significant way. Some samples below. This is one time that a really good digital camera can make it much easier to test and evaluate a procedure. I tested Gtechniq Nanotech Glass Polish, Renaissance Micro-Crystalline Wax Polish, Rain-X Original and Chemical Guys Lucent Spray Shine.
No Filter
Sanded, before Gtechniq
Gtechniq Polish
Sanded, before Rain-X
Rain-X, after
Sanded, before Lucent Spray Shine
After Lucent Spray shine
sanded, before Renaissance Wax
After Renaissance Wax
The two products which seemed to give the best results were Rain-X and Chemical Guys Lucent Spray shine. I also tried Renaissance Wax and a polish. The polish was a complete bust.
I then tested the Rain-X on a Goerz 12 inch Apochromatic Artar lens and the Chemical Guys Lucent on a Schneider 180mm Componon lens. Of course, these lenses were not equally degraded. I put the Nikon D-850 on the back of my Toyo Camera (set-up picture below), and shot through these lenses. It was very difficult to establish which product was better in this case, but both were useful. Results are attached below. Please note that I was evaluating full size digital files and those full-size files are not attached to this post. If you would like to study the full-size files please contact me at john@siskinphto.com to arrange to get full size raw files.
Toyo camera test set-up, front
Toyo camera test set-up back
Schneider 180mm Componon AFTER Lucent Spray shine
Schneider 180mm Componon BEFORE Lucent Spray shine
12 inch Goerz Artar BEFORE Rain-x
12 inch Goerz Artar AFTER Rain-X
I tried the Chemical Guys Lucent product on the lens which I’ve been working on. I would like to believe there is a significant but I really don’t see it. This lens is extremely small and had many micro scratches, so the fact that there is no significant difference is not a reason to discount the use of the product in other situations. It is helpful that the product hasn’t seemed to reduce the lens quality in any tests. Both tests were done using Kodak T-Max 100 film.
30mm lens AFTER Lucent Spray Shine
30mm lens test BEFORE Lucent Spray Shine
If anyone has additional experience in this kind of lens repair, I would be quite interested to know of it!
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