How to clean lenses/objectives properly?

Planapo · Post by **Planapo** » Thu May 08, 2008 11:08 am

Finally, I found a way to mount two of my cine lenses, and I now want to put them to some tests. But on one I discovered finger prints (no, not mine!:) ) that I first want to clean off.

I am not experienced in lens cleaning and of course I don´t want to ruin the lens or its coatings, hence I searched the web for a reliable detailed description of the cleaning process. On the site of Zeiss I found one, I think it can be useful for other people aboard, so here is the link to the English version of the pdf.

However, what I find a bit thought-provoking is that Zeiss recommends two washing-up liquids (brands "Fairy ultra" and "Fit") but we all know that those are often advertised for by stickers saying "new formula, even stronger now" etc. . So how can Zeiss be sure that a change in the ingredients of such detergents will not eventually be problematic for the lens/objective (coatings)?

In my eyes more precise and trustworthy is the given recipe for their Optical Cleaning Solution L (consisting of 85 % petroleum ether, pro analysi, bp < 44 °C and 15 % isopropanol, pro analysi). I could pour this solution quickly together but I am a bit hesitant as I am not sure if it can be safely applied to lenses like cine lenses, enlarger lenses and others not made by Zeiss?

So any helpful advice of the more advanced photographers on how to clean lenses safely, especially to get rid off such greasy finger prints without risking to damage the lens or its coatings, would be much welcomed.

Thanking you in advance
Betty

Charles Krebs · Post by **Charles Krebs** » Thu May 08, 2008 12:01 pm

Betty,

Probably the most important aspect is to avoid "grinding" anything into the lens surface. So it is best to work in "stages". First blow any loose material off with a squeeze bulb type blower, or carefully with "canned air". Then lightly use a soft brush designed for use on lenses. When you get down to real contact with the lens surface be sure that you never "rub" something that is completely dry on the lens. The Zeiss publication you referenced is excellent. Unfortunately the lens tissue they strongly recommend it extremely expensive and difficult to locate. While I have some of the Whatman 105 paper, there are other quality tissues that work just as well. Regardless of the tissue you use, a good method is to fold over a few sheets several times and then tear it in half. This leaves a nice soft edge ragged edge that can be bunched together to use sort of like a brush (Try not to get any finger oils on the parts that will contact the lens).

For a mild soapy solution, (as suggected in the Zeiss document) , I would choose one of the recommended brands that has no additives (such as disinfectants and scents. Avoid anything with ammonia in the formula!) Lately it seems that the manufacturers are making these solutions more concentrated, so just dilute it significantly more than suggested.

I've started using their "Optical Cleaning Solution L", but mainly for the microscope objectives that have immersion oil on them (which is a real pain to get off... especially if you accidentally get it onto a non-immersion objective!) I've used it on multi-coated camera lens filters with good results as well.

With any liquids, water or petroleum based, be sure to use it in on the tissue in small amounts that will not allow any to seep or drip "into" the lens itself.

Perl · Post by **Perl** » Thu May 08, 2008 11:37 pm

Hi

I Use Zeiss lens cleaning kit with cotton pins
it work perfect (see picture)

No chance to destroy lens coating if you not grinding it off
or use acid / strong cleaning stuff - not on quality lenses

Most important are as Charlie say do it in steps

1.blow of
2.use cleaning agents on cotton tip (not to much) and do it
in right motions as described in Zeiss cleaning manual
3. use dry cotton tip to finish

This works perfect for me - both on Microscope Objective and Binocular

Regards

Pär Lundqvist
Sweden

Planapo · Post by **Planapo** » Sat May 10, 2008 2:27 am

Thanks Charles and Pär for your comments, I feel more confindent now to use the Zeiss Solution L on my glass. As to the tissue I had ordered the Kerma cotton for ophthalmology which Zeiss recommends from my pharmacist around the corner. It has arrived, 100 g for 3 Euros and boy ... 100 g cotton is quite a heap, so that will do for decades of lens cleaning to come.

As to the soaps, well I found almost one shelf meter of various "Fairy Ultra" versions at the super market but no one without scents, same with "Fit" and hah! .. as expected "Fit" has an inscription on the label saying: "New: more fat dissolving power" and a lemon smell too. So I went to my optician and got a mild tenside without scents that is meant to be used for coated glass (both mineral and plastics) of spectacles, and was assured that it won´t do any harm to all other kinds of coated optical glass either.

Thanks again,
Betty

Charles Krebs · Post by **Charles Krebs** » Sat May 10, 2008 9:41 am

Betty,
Actually, I doubt a highly diluted scented dish-washing liquid would really be a problem, but now you know you are OK. Some of these optics get very expensive and can be hard to replace, so why fool around with cleaning materials that might cause damage.

Harold Gough · Post by **Harold Gough** » Sat May 10, 2008 10:45 am

Two products to note:

Opti-clean and ROR. The former has been safely used on phenomenally expensive broadcast TV lenses.

Harold

augusthouse · Post by **augusthouse** » Sun May 11, 2008 2:42 am

The Carl Zeiss kits that Pär mentioned are going for US$19.95 out of Germany.

item#:110250810180

Craig

Perl · Post by **Perl** » Mon May 12, 2008 6:53 am

Hi

One more thing is if you use the Zeiss kit
i recomended - Do not spray directly on lens (Objective)
spray the fluid on cotton tip and then apply it
on the lens (Not much is requred)

Otherwise the solution will be al over the objective

Best Regards
Pär

Harold Gough · Post by **Harold Gough** » Wed May 14, 2008 5:31 am

Perl wrote:Hi

One more thing is if you use the Zeiss kit
i recomended - Do not spray directly on lens (Objective)
spray the fluid on cotton tip and then apply it
on the lens (Not much is requred)

Otherwise the solution will be al over the objective

Best Regards
Pär

I have heard of such liquids, when directly applied, causing rapid cooling of the glass, fracturing the lens.

Harold

DaveW · Post by **DaveW** » Wed May 14, 2008 10:26 am

Whilst I know people used to use a drop of washing up liquid as a wetting agent for washing films, I always understood washing up liquid contained salt (just as salt is added in a dishwasher). I would have thought therefore as salt is corrosive it would be unwise to use washing up liquid in case it got into the lens mounts?

There are many proper lens cleaning fluids on the market so why risk it? See:-

http://www.earthboundlight.com/phototip ... aning.html

http://www.earthboundlight.com/phototip ... aning.html

Just a note on sensor cleaning of digital cameras too, some of the new Nikon's and I believe the Canon's and Sony Alpha's are now using a new anti-static sensor coating (ITO = Indium Tin Oxide) which some of the conventional sensor cleaning fluids can damage or remove, so you need one of the newer ITO safe cleaning fluids for them.

Apparently you can remove or damage the coating without noticing any optical effects, but your sensor will attract dust quicker, which is probably why some claim they still use the old type cleaning fluids with no problems. See:-

http://www.earthboundlight.com/phototip ... aning.html

http://en.wikipedia.org/wiki/Indium_tin_oxide

The camera manufacturers usually don't advise you what to clean the sensor with but just tell you to return it to their service agents when the sensor needs cleaning, which provides them with a nice regular income!

DaveW

Particle_Man · Post by **Particle_Man** » Wed May 14, 2008 10:58 am

I use Isopropyl alcohol and pec pads for my lens cleaning. Could work with a microfibre cloth, but have yet to find a proper one.

Perl · Post by **Perl** » Thu May 15, 2008 11:56 pm

Hi

Will not recomend pure Isopropyl alcohol
it will destroy cementing between lenses
and dry out gum/plastic in immersion front lens

Use the Lens Cleaning kit made for it ,
DO NOT MAKE CLEANING MIXTURES SELF

Pär Lundqvist
Sweden

g4lab · Post by **g4lab** » Fri May 23, 2008 8:17 pm

I have lots of optical equipment.

I try to only use Kodak lens cleaning solution. I do have ROR on hand as well, but I prefer to use Kodak solution.

After blowing and brushing the optic, then Kodak lens cleaner on Zeiss lens tissue or a microfiber cloth , which I think are one of the great inventions of western civilization. I usually put a Q tip behind them as a pusher tool and pad and excess lens cleaner absorber.

I don't touch a q tip to the optic.
I do have various semiconductor grade cleanroom swabs but they usually aren't necessary except possibly for new arrivals.

Oil immersion objectives are a separate case from almost all other optics.
They really are designed to be flushed off with Xylene to cut the immersion oil. Of course one would want to use an excellent grade. Then follow with a more conventional cleaner or just leave it at the Xylene cleaned level. You will be immersing it again soon anyway and you don't want to overdo cleaning.

"Primum non nocere" First do no harm.