Cleaning Lenses

[Cristian Carceller]

Hey,

 

 

 

I was wondering what are some of the best techniques and steps on cleaning lenses. What tools to be used, what to do and what not to do, and the techniques when actually cleaning the front elements of the lens. I have heard of many different techniques but some are very different from others,

 

 

Thank you for you Time!

[Dom Jaeger]

One of the great things about this site is the wealth of information contained in the archives, and this kind of question has probably been asked a dozen times over the years. For example:

 

http://www.cinematography.com/index.php?showtopic=36429&hl=%20cleaning%20%20lenses&st=0

 

So it's always worth doing a search of the archives before posting a question that's not particularly specific. But anyway here's my take, since I'm only a relatively new contributor..

 

The first thing I'd emphasise is never try to clean a lens without blowing off any surface debris first. If there's anything guaranteed to scratch an element it's dragging a hard speck across the surface with a tissue or cloth. I've never had a problem blowing air onto a front or rear element. Canned air might possibly spatter the surface with moisture, but that's easily cleaned off.

 

My personal preference is to then use a tissue folded into a coned wedge dipped in isopropyl alcohol, starting from the centre and spiraling out to the edges. I roll the tissue slowly as I go to lift off any particles that the air didn't remove. If it's a large element I might use several tissues. If there are stubborn marks I'll use acetone, maybe with a cotton bud, being careful to avoid any edge blacking. Sometimes lens cleaners like Pancro or Rosco (I use a German brand called Sidolin) remove marks that neither alcohol nor acetone can clean, but I find that they often leave streaks or residue so I need to go over the surface again with alcohol.

 

Once I'm certain the surface is clean I might do the breath and buff thing, but it's generally not necessary, and if you're using a micro-fibre cloth you need to make sure the cloth is clean.

 

Bear in mind I'm a lens tech doing this at my bench. In the field people have different techniques, but as a general rule the less you need to clean a lens the better. The damaging things are usually fingerprints, spittle, and salt crystals (beach sand, sea breeze etc), which can all etch into the element coating if left for too long.