What's the best cleaning method?

Dust can usually be blown off, but when I recently bought some filters from a supplier of used equipment, one of them was particularly greasy and grubby (the filter - not the supplier!) so I asked him to clean it. He used a fluid, from an unmarked bottle and a soft cloth, but was extremely reluctant to tell me what the liquid was.

 

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Presumably glass filters could be washed with detergent and water to remove grease (eg finger prints and other grime). I guess it wouldn't be safe to use a liquid or solvent on a lens, in case it damaged the special anti-reflective vapour deposited coating.

 

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What is the recommended method for cleaning optics?

I would bet the farm that the magical mystery cleaning fluid was ROR-1 (Residual Oil Remover), great stuff that was recently discussed on the Leica list. Everyone was amazed that so many others knew of this little "secret". You first blow off the dust particles with canned air, then use a little ROR-1 on a microfiber lens cloth such as Luminex or Photo-Clear. Works great...

 

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Jim

Thanks. Does anyone know if ROR-1 is available in the UK? If so where? If not, where can it be obtained in the US, via mail order?

At the risk of accusations of heresy, I'll tell you how I do it:

First blow away all the dust you can. I'd probably use compressed air, but I don't have any. Next, dampen a spot on a clean, lint-free cloth---a linen tea-towl works well---with the (alcohol-based?) cleaner that's safe for cleaning plastic eye-glass lenses. If you care a lot about the lens, wipe only once before using a new spot on your clean cloth. I use only the weight of the cloth against the lens, rather than adding pressure with my finger. Q-tips work well for very small lenses, such as eye-pieces.

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Whatever the details of your technique, I believe that there are two very important points:

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<li>Put the cleaning fluid on the cloth, not the lens, and don't use too much fluid. You don't want extra fluid to run inside your lens.<p></li>

<li>Dust contains fine sand and other hard, gritty material. Any scratches will be due to rubbing the dust between your cloth and the glass. Wipe as gently as possible and switch to new, clean spot on your cloth very, very frequently. Using a clean spot for each wipe is far more important than what type of cloth you use. Also, use short, gentle, wiping motions that lift the dirt, not smear it around or rub it into the surface of the lens. Most cotton or similar cloths are far softer than the lens coating and far, far softer than the grit contained in dust. Similarly, any fluid that will clean grease without damaging your lens coatings and leaves no residue is fine. For glass, some people swear by Windex, but <em>not</em>the generic imitations. The plastic eye-glass fluid is safe, inexpensive and readily available, though.<p></li>

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If you have removed the element, for some reason, then an even better way to start is letting room temperature water run <em>gently</em> over the surface of the lens. The water will often rinse off some more dust, further reducing the risk of scratches. I personally don't do this with filters because I can't dry between the glass and metal mounting ring. A water rinse is an excellent starting point for cleaning eye-glasses, should you wear them. This approach is essential for cleaning the extremely delicate surfaces such as the front-silvered mirrors found in reflector-style telescopes or mirror lenses. Use distilled water with such delicate surfaces so any drops will leave no residue and need not be wiped dry.

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All that being said, some modern, high-quality coatings are remarkably hard and scratch resistant. This fact has allowed their use in eye-glass lenses, which typically receive frequent and relatively rough cleaning. I met someone who shamelessly cleans their Zeiss eye glasses on anything, any time, anywhere. After a couple of years of this treatment I was very surprised that I could detect no scatches or flare. I'm not advocating this practice and indeed I'm sure there's a lot of variation between the different coatings from different manufacturers, but perhaps hard coatings are a benefit of high-quality, modern optics.

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Finally, remember that if there's only a little dust, it may be better to leave well enough alone. Left alone, the dust is not likely to damage your lens and, if there's only a little, may not decrease the image quality significantly. Cleaning always involves risk.

Here's the link to the info site about ROR-1. I am NOT affiliated in any way with the manufacturer, nor do I have any stake in the product at all. Just wanted to pass along the information.

 

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Jim

 

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http://www.ror.net/index.htm

ROR is available from B&H, if you can't find it locally. I'd never heard of the stuff until somebody mentioned it on the Leica list, but then discovered it's a standard shelf item at my local photo dealer. I'd looked at it for years, never knew what it was, and just hadn't bothered to pick it up and read the label.

For my telescopic mirrors I always used dishwashing detergent, a soft camel hair brush and immersed the whole deal under running water at room temperture. This was the recommended method from the engineers themselves, and it should be noted that mirror optics have far higher tolerences than reflex (camera) lenses, although they tend to lack the integrated coatings.

 

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Rather than resort to constantly cleaning my camera lenses I opted instead to use a high quality filter and let it take the abuse. Much easier to wash than a lens assembly. Only one errant piece of dust and no matter how soft your cloth or high-tech your solution and you'll have a scratch on your lens.

 

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//scott

A few responses that came in to the question need to be challenged.

One recommendation was to use Windex. This is not a good idea. It contains ammonia, and may damage lens coatings.

Another was to use an alcohol-based solvent. My experience with this has not been satisfactory. I tried using isopropyl alcohol (rubbing alcohol) from a pharmacy. It left a thin white film on the glass. I suspect it has something to do with the purity of the solvent I used. Also, alcohols may penetrate around the lens edges, if used too liberally, and affect the lubricants as well as the lens cement.

I tried ROR yesterday for the first time and I am very pleased with it, having used Kodak lens cleaner prior to that. The trouble I find with Kodak lens cleaner is that I have to clean the lens twice: once with the lens cleaner to remove what is on the lens, and a second time with clean lens tissue to remove the thin film left by the lens cleaner itself.

I also recommend using Kimwipes EX-L tissues. You can order them in small boxes of 280 sheets. They are perfect for the darkroom. They are single-ply, extra-low lint wipes, similar to Kodak's lens cleaning tissue, but less expensive.