PDA

View Full Version : How to clean a lens?



Mareike
15-Oct-2005, 13:46
Hello,

Im just about to start with LF and now my first lens was shipped (Schneider Geronar 210mm, was a display model). It looked perfect beside a finger print on the glas inside.
So I tried to clean it: first only with a microfiber cloth and a Anti-static Tiger Cloth (Kinetronic) but there were wiper traces. I also tried to use a small amount of lens cleaning solution but it didnt help.

Im a bit afraid I could have damaged the lens.
What is the best way to clean a lens?

I would appreciate if you could help me with your experience.

Regards, Mareike

Mareike
15-Oct-2005, 13:48
Sorry, the lens is a Rodenstock Geronar.

paulr
15-Oct-2005, 15:10
http://www.schneideroptics.com/info/white_papers/lens_cleaning.pdf

Eric Leppanen
15-Oct-2005, 16:26
www.schneideroptics.com/photo-clear/ (http://www.schneideroptics.com/photo-clear/)

John Kasaian
15-Oct-2005, 21:02
Vodka!

Have a glass while trying to decide what to do next, then another glass after you've nearly convinced yourself that cleaning 'whisps' won't have any noticeable effect anyway. Have a third glass to celebrate all the money you'll save by buying used lenses with cleaning 'whisps.'
Resist the temptation to polish off your vodka---keep some around for cleaning your lenses ;-)

ronald moravec
15-Oct-2005, 21:20
First blow of debris with a hand blower. Brush off any more with a hand brush. Then attack it with proper cloth and fluids.

Attempting to polish a new clear coat car, plexiglass window, or camera lens without first removing solid debris will result in scratches to the finish, Even dust will act as abrasive grits.

I use microfiber cloths or old linen or cotton cloths that have been washed 100 times. Put fluid on the cloth, never on the glass as it can run inside.

Always use gentle pressure to minimise the chance of scratching. Keep the cloths in a sealed plastic bag when not in use. If they get dirty from the atmosphere, you can rub the dirt into the lens.

Finally clean as little as possible. Blow off what you can and stop. Needless scrubbing does more damage than good.

Finger prints are made of acid deposits and will etch into the glass if left long enough, so clean these or better yet, don`t touch the glass.

Then there are uv filters for those just can`t be careful. I see little degragation from them on large format work.

Wilbur Wong
15-Oct-2005, 21:23
I use Methanol - dries without a trace. I don't remember where I got that from, but I've been using it for years now. For source, McMaster-Carr. $12 for a quart, 16 for a gallon to last a lifetime.

Emrehan Zeybekoglu
16-Oct-2005, 06:57
Doesn't methanol harm the coating on the lens?

Frank Petronio
16-Oct-2005, 08:36
Outside of actual debris, I only clean fingerprints and sea spray immediately. Cleaning the small wipe marks, especially on the softer coatings of older lenses (1960s - 70s era) can make things worse.

Frank Petronio
16-Oct-2005, 08:37
Also, the "Lens Pen" is very good for hard to clean oily smudges. I even used it on a $2500 Leica lens, but not without a moment of heart wrenching angst.

John_4185
16-Oct-2005, 11:21
Aw, when my lenses get dusty I just throw 'em away.

Seriously, a funny aside. When I was a kid, a (now famous) photographer showed me how to clean a lens by first taking a swig of whiskey, then 'hush' a breath to fog the surface before wiping it. Really, I think he was just trying to freak me out. When I tried it on my (plastic) lens, I got sick ... it gets worse, so I'll stop here.

Mareike
16-Oct-2005, 14:24
Thanks to all of you for your advice.

The most important thing to know was, if any cleaning liquid should be used or not.
I tried again and it looks better now. There are still wipe marks, but they are hardly visible. So I better leave it like it is now.

(A special "Thank you" to John. After the third glass of wodka I had a brilliant idea: I just took another glass of wodka and dipped the lens inside. I cannot see any wipe marks any longer.)

Frank Petronio
16-Oct-2005, 14:45
Thomas Tomsey's camera repair books discuss how he cleans lenses - he uses Windex and Kleenex. So perhaps we are all being too anal.

John Layton
16-Oct-2005, 15:34
Buy yourself a packet of Kodak lens tissues (other kinds tend to be damaging) and a bottle of Formula MC lens cleaner. Take out two tissues (per lens) and tear one of these in half. Tear off a fresh end from the half tissue and fold this over and roll it to make a little brush, using the torn edges on the lens. Brush gently, from the middle to the edges, and be very careful when working around the edge of the lens, an area which can tend to trap dirt. Dispose of this piece. Next, fold the other half - tissue a couple of times and moisten with a drop or two of the MC, and gently wipe the lens, in a circular motion, starting in the middle and working towards the edges, stopping just short of the edges to avoid having any liquid seeping into the mount. Now, fold the other whole tissue in half, and use this to polish the lens, again working from the center towards the edges. The thing about formula MC is that it will take a bit of gentle polishing to remove all the residue, but its worth it as MC is self-protective in use. You'll need to "unfold" the tissue and refold so you can use the inner surfaces for a final polish - and should inspect the glass surfaces under an oblique light source to make sure they're truly clean.

OK - lest anyone think this is overly obsessive - it only takes a minute and is only really necessary in the case of fingerprints or other oily smudges, and of course salt spray. Don't sweat about dust - unless there's lots of it. I do recommend lens tissue over microfiber, for the simple reason that the tissue is thrown out after using it. A microfiber is designed to pull in dirt - great when its absolutely clean but increasingly risky with each use. I usually do keep a clean microfiber handy - but usually use this to clean viewfinders, loupes, and ground glass surfaces.

Dan Jolicoeur
17-Oct-2005, 08:00
Methanol is what the manufacturers use. It will not damage any coatings, except clean the ones deposited by other cleaning fluids; call the manufacturer of your lens and ask them.

Howard Berg
17-Oct-2005, 16:32
At work I have a $150,000 pulsed Ti:sapphire laser and have to regularly clean its mirrors. The service engineer showed me how: use Kodak lens tissue, folded and clamped in a hemostat without touching the part of the tissue that will do the cleaning, and moisten it with a drop or two of reagent-grade methanol. Swipe the mirror one time with the methanol-moistened wipe. i usually end up using lots of the tissue. I use the same method for my LF lens and it works beautifully. As mentioned in the responses above, be sure not to do this if there is debris on the lens or that will grind the coating.