Cleaning Glass on old lenses

[David Aimone]

Sincere apologies for asking a question that's probably been answered before, but a search for this brought up <everything> but the answer...

What is the best way to clean the glass on older lenses (assembled)?

Coming from the digital camera world, I would have just used a combination of a blower, lens pen or special cloth/paper with solution.

But these lenses are much older, and to me, much more valuable (even if they don't cost more). So the lenses that I have are all pretty decent, but they are collecting more dust and other contaminants from all sources (pollen, dust, salt air, etc.). I don't want to scratch them.

What is a safe, gentle and effective method for regular cleaning?

[domaz]

If they are uncoating its easier to clean than modern lenses- just use the methods you always use. If you have a lens with an old coating like the Kodak ektars I would be hesitant to even touch them unless it's absolutely necessary. Those coatings are very soft.

[David Aimone]

I have some old brass lenses, I assume uncoated. I will gently air dust, then wet clean.

Also, what about newer old lenses (Rodenstocks, Nikkors, etc.) from the late 20th century?

[IanG]

If they are uncoating its easier to clean than modern lenses- just use the methods you always use. If you have a lens with an old coating like the Kodak ektars I would be hesitant to even touch them unless it's absolutely necessary. Those coatings are very soft.

Some uncoated glass is extremely soft, usually 1930's when newer glasses allowed faster lenes, particularly the glass used by Leitz for lenses like Summar's, and Zeiss used similar glass in some of their lenses.

Most coated lenses have harder glass but yes some coatings can be soft, so cleaning with a liquid cleaner is safer & less abrasive. It's surprising just how much dirt can have accumulated on a lens, particularly when previous cleans have just pushed the dirt to the edges.

Ian

[David Aimone]

The older lenses are probably 1900 or earlier; the newer probably at least 1970 onward. I'm just looking to do this safely.

Some uncoated glass is extremely soft, usually 1930's when newer glasses allowed faster lenes, particularly the glass used by Leitz for lenses like Summar's, and Zeiss used similar glass in some of their lenses.

Most coated lenses have harder glass but yes some coatings can be soft, so cleaning with a liquid cleaner is safer & less abrasive. It's surprising just how much dirt can have accumulated on a lens, particularly when previous cleans have just pushed the dirt to the edges.

Ian

[Dan Fromm]

If they are uncoating its easier to clean than modern lenses- just use the methods you always use. If you have a lens with an old coating like the Kodak ektars I would be hesitant to even touch them unless it's absolutely necessary. Those coatings are very soft.

Are you sure? Have you damaged Ektars by cleaning them or are you repeating old wives' tales?

I ask because I have a couple each of 101/4.5 and 127/4.7 Ektars whose coatings on all accessible surfaces seem as hard as the coatings on newer lenses.

[domaz]

Are you sure? Have you damaged Ektars by cleaning them or are you repeating old wives' tales?

I ask because I have a couple each of 101/4.5 and 127/4.7 Ektars whose coatings on all accessible surfaces seem as hard as the coatings on newer lenses.

No haven't personally damaged any true enough. My 203mm Ektar does have a ton of coating scratches though but it has an unknown history so who knows if it was bad cleaning that did it or just bad handling.

[Robert A. Zeichner]

The guidelines for lens cleaning are pretty simple:

1. First blow off any loose dust or dirt.
2. Use a soft piece of cotton cloth (old T-shirts that have been laundered a lot of times work best) to gently push off any more stubborn, but nonetheless loose pieces of crap that might resist the blowing.
3. Dampen a clean piece of that laundered cotton T-shirt with some good quality lens cleaning fluid. I use diluted Butylcelosolve, which you may have a tough time getting, but some clean acetone will work well if there are a lot of greasy smudges on the surface. If that is not available, some Kodak or Tiffen lens cleaning fluid works, although less effectively on grease. Gently wipe the surface and avoid getting the fluid near the outer margins where it could get down under the retaining ring.
4. Follow up with your breath and another clean section of cloth.

Alternatively, one of those micro-fiber cleaning cloths that Schneider and other offer will work in lieu of the cotton cloth.

This technique has worked for me for many years on all vintages of optics. The biggest danger is failing to clear the surface of loose, abrasive crap that will just scratch the coating or even worse, the glass when you start the wiping process.

[Fotoguy20d]

I find Ektar coating can scratch very easily - never dry wipe a dirty/dusty lens (old or new) - think sandpaper. I never clean my modern lenses - I clean the cheap filter I keep in front of it (but that's another thread with lots of argument potential). Someone will probably cringe at the way I routinely clean old lenses (and I've gotten some really filthy ones off the bay). I remove the cells from the barrel to whatever extent possible (if a piece of glass is permanently installed, use care with this method) and then wash them in windex with a paper towel. On a truly filthy piece of glass, I'll often rinse first in water, spray, let it run off, and then spray again - the less grit in the solution the better. Use caution around cemented lenses - try to keep the solvent out of the balsam (in some cases, perhaps just use water). And wipe with care. YMMV but its worked quite well for me.

Dan

[IanG]

I find Ektar coating can scratch very easily - never dry wipe a dirty/dusty lens (old or new) - think sandpaper.
Dan

That's the best advice.

With early coatings there can be issues. Some, like Dan Fromm says, are very hard. My early 1950's 150mm CZJ Tessar is as good as modern MC, in hardness and effectiveness - just rather blue, a cast if used for colour

But I have had lenses with soft coatings, that will polish off if cleaned dry. My 101?mm Ektar's OK but has cleaning marks so some things soft.

Ian