How to clean a lens?

[bill_1041]

What is the recommended way to gently clean the front and rear surfaces of my Ek tar lens? Despite keeping my lens caps in place religiously, I've acquired some spots that I know will come off - but how to clean it without damage?

I'm looking for the "tried and true" methods: types of cleaning cloths, cleaning solutions, techniques, etc.

Thanks as always - Bill

[TAN K H]

First, make sure that for whichever lens you're cleaning, the coating is a hard one.

You could use ROR (residual oil remover - http://www.ror.net/) or use Windex.

The best applicator for me is a good, clean, microfibre cloth. Put the cleaning fluid on the cloth, NOT the lens.

Windex does a really splendid job on all my lenses. It cleans up stuff that Kodak's Lens Cleaner doesn't. I also use it to clean the inner elements on lenses that are not too complex in construction. (I understand that the typical fungus cleaner in repair labs is 50% ammonia, 50% Hydrogen Peroxide - not sure what concentrations)

Ammonia (the main cleaning agent in Windex) kills fungus growth and cleans up haze fantastically well. I had two APO Lanthars that had fungus growth in them (my friend's dad who owns these borrowed lenses simply did not believe in humidity controlled storage!). Another lens with bad haze cleaned up beautifully with Windex as well - Kodak Lens Cleaning Fluid, and alcohol simply did not work.

The last lens needing major cleaning was my cousin's badly fungus-ed Nikkor 20mm. There was a really bad growth on the rear element - the fungus was so 'mature' that you could feel its contours with your fingertip, that's how bad it was. A swab with Windex, and presto, gone. Completely clean. That's not to say that if the fungus has eaten into the coating, the coating can be magically fixed. But Windex will ensure that all the fungus is killed and removed.

FWIW, ROR has some ammonia in its formulation as well.

Whatever it is, DO NOT BE FORCEFUL. You don't have to be overly gentle, but use your common sense. Use any cleaning fluid sparingly.

[TAN K H]

Oh, you may want to check out Bob Monaghan's site as well. He has page on lens cleaning (what topic hasn't that fella covered???)

http://www.smu.edu/~rmonagha/broncleaning.html

[Pete Andrews]

As a first resort, a soft Sable brush is the answer, or one of the specially made "blower" brushes with a little air puffer attached to it. Whatever you do, keep your fingers off the brush though, or you'll remove the dust and replace it with a thin grease film. Disposable paper lens tissues should deal with any more stubborn muck; use them once and throw them away. I use Whatman 105 optical tissue, with a little "heavy breathing" and have never had a problem with cleaning abrasion.

[Michael Kadillak]

I asked this question a while ago concerning smudges. At the bottom of the archive list under lenses, Cleaning Smudges and the responses can be found half way through the listing.

[Michael S. Briggs]

The key to not scratching your lens is removing dust particles as gently as possible, and before wiping the lens. To be avoided is converting your lens tissue into sandpaper by scrubing hard while dust is still on the glass. I like to use canned air, then a Static Master brush. The radioactivity discharges the static electricity that makes dust stick to the glass. Then use lens paper/cloth with some fluid to remove any grease. I get good results with Pec Pads and Windex. Condensed moisture from your breath works well on slightly soiled lenses.

[Struan Gray]

1) remove any dust with a blower or very soft brush. Mineral dust from beaches and deserts does a lovely job of scratching glass if it's still there at stage 2.

2) breath on the lens and wipe in small circles with a soft cotton cloth (a well-washed handkerchief is perfect). Repeat until your breath clears from the surface so fast that you don't have time to wipe. Don't use paper tissues: even lab-grade ones like Kimwipes can scratch optics.

2a): This stage is almost never necessary, but for stubborn stains and greasy spots wipe with, in order of effectiveness and agressiveness, methanol, ethanol, isopropyl alcohol, hexane, or acetone. Put the solvent on a rag or Q-tip, don't spray it on the element. Use chemist-grade solutions, not household cleaners, and be aware that more agressive solvents may attack plastics, paints and some iris and shutter leaves.

If you have a lot of grime and/or dust on the elements there is a high-tech solution to stage 1. Opticlean is a polymer that is spread on the lens, allowed to dry, and then peeled off taking both dust and some sorts of grease with it. It sounds like magic, but unlike some previous products that were supposed to do this, it really works: the people down the hall from me use it to clean their terawatt laser components. You can buy direct:

http://www.dantronix.com/dantronix/oppolsec.html

Or MX2 in the channel islands (www.mx2.com) sell small 6ml kits which are enough for occasional cleaning of photo lenses.

Finally, the Melles Griot catalogue is a wonderful, free source of information about lenses, coatings and optics in general. They sell lab-grade cleaning tools such as swaps which won't leave lint and onetime wiping cloths. Probably overkill for the photographer, but the site is worth perusing in any case. They're online at www.mellesgriot.com.

[Emil Ems]

I recently acquired a package of Opticlean, which appeared to be the ideal solution to cleaning lenses.

However, I had some problems with applying the solution, which I would like to share with the photographic community. Possibly, someone else has already found solutions to those problems.

I first applied the solution as recommended, that is, I did not apply it all the way to the edge of the glass, leaving a small uncleaned rim. The problem with this approach is that it is very difficult to remove the hardened solution with the tape supplied by the producer without leaving a smudge on the rim.

To solve the latter problem I then applied the solution all the way to the rim of the glass and a little bit beyond. This solved the problem with applying the tape, since I could stick it to the hardened solution from the rim. However, the hardened solution was not completely removable. At the rim it broke, leaving me with pieces of plastic sticking to glass and rim. The big question now is how to remove these pieces of plastic without damaging the glass. I tried to do it with a pincette, but that just did not work. So I am still at a loss. Has anyone a suggestion to help me out? Or should Opticlean be used only on very large glass surfaces where this problem would not arise?

[Struan Gray]

My spies tell me that Opticlean does work best with unmounted optics with no edge rim, but they don't get bits sticking like this when they clean the camera lenses they have. Dantronix recommend using a thicker layer when cleaning anodised surfaces, so perhaps you're not using enough.

In any case, with lenses that have been used in a non-lab environment - where greasy stains are more likely - I would use Opticlean as a first dust-removal stage prior to the breathing and wiping I described. In which case removing a tape smear from the rim is easy. If you still get bits of polymer sticking round the edge a clean wooden or plastic spatula won't hurt the paint, so pick at it on the rim and peel it off the glass.

[Paul Schilliger]

I had read in a cleaning products company advert that a thin layer of oil on the lens can considerably reduce the quantity of light that passes through! I think it was more than half a f-stop! It had to do with the multilayer that was made inoperant. Any thought or confirmation?