If there is a "stubborn" stain it may in fact already be a cleaning mark, i.e. damage to the AR coating.
Originally Posted by Dave Dawson
I would agree with the injunction not to clean unnecessarily, even if your cleaning cloth isn't abrasive it might pick up something that is and cause damage.
I find the microfibre cloths sold for optics cleaning are effective and safe on modern camera lens coatings (which are harder and more durable than ones from decades ago).
Blow off any dust with canned air or a blower brush first (read the instructions on canned air carefully).
If you want to use anything liquid you might start with "windex" window cleaner (vers slightly dampen your cleaning cloth only) since this will remove polar, non-polar and mixed soils. You may need to follow up with the highest purity isopropanol you can obtain since windex itself can leave stains.
Wipe from the centre to the edge of the surface.
(BTW I would vote for the no-filter-but-use-a-lens-hood-option)
With the possible exception of B&W, filters don't meet the quality of good optics. Try two same-time photos - one with and one without. I have and there is a difference' albeit subtle. I do put filters on my lenses from transportation, but remove them before shooting.
Agree with DaveO re cleaning. As seldom as possible, (always blow off the lens after use) but whenever necessary.
"Why is there always a better way?"
... And the first raindrop falling on your hydrophobic lens (not protected by a UV ... or... barrier) will render it ... what? Useless? Let me redirect you to what I wrote - the important part is DON'T!! if at all possible.
Originally Posted by keithwms
Go ahead - disagree!! You are perfectly entitled to do so.
Since I am already being a contrarian in this post, permit me to also disagree with your assessment that a damaged Leicablad lens is the saddest sight in all of photography.
??? - WHO intended what??? I'll agree that the Optical Engineers were involved - I've known and worked with a few.
To me the saddest sight in all of photography is a fantastic lens with a UV filter on it. IMHO a person who is willing to pay the bucks for fantastic lens should also be willing to take the risk of letting the lens do what it can, in all its naked splendour.... as the lens engineers (and indeed, God Himself) intended for it to be used.
Uh ... Permit me to say that it somewhat presumptuous to assume the intent of the Great Creator. Possibly, in some grotto, on some Chapel ceiling ... we might discover a painting of the GREAT ZOT ripping a filter from a lens amid flashes of lightning and thunderous peals of thunder - so far I know of none even remotely applicable. Until I do, I'll limit any discussion to the engineers.
While I'm at it - I have never encountered ANY optical engineer with such a negative evaluation of filters. Period. As long as the geometry of the filter is reasonably sound there is/ can be - VERY little effect on the ray tracing and finally, image. Way back, I was presented with the idea that the thickness of a filter had a negative effect on image quality. As an experiment, I set up a lens on the optical bench, observed its characteristics - and introduced what would be an unreasonably thick filter, in the form of a double surfaced fused quartz optical flat. Fused quartz, with a HIGH refractive index, complete with "seeds" (small), and -- ~ 40 - 50mm thick. End result? No ... NO significant degradation of image quality.
Now ... Water is not appropriate for removing oils. True.
In trying to remember, I can't think of any instance where I have encountered oil contamination, Must be that my (demon) UV filters are woring well.
But then - there are those who would advocate the use of Drano and a grinding wheel...
We did have one techni ... uh, well not quite ... who decided to clean a lot of 20 specially coated (20 layers) lenses... his choice of cleaning media was a common pencil eraser.
He never got a second chance.
BTW ... Surfactant? Wouldn't that decrease the surface tension and increase the possibilty of accidental incursion ito the innards of the lens?
Ed Sukach, FFP.
Any suggestions on what to get from the chemist to shift those stuborn stains? I geuss pure alcohol will be in there somewhere??
Canned air; camel's hair brush. Look at surface obliquely to make sure all grit is off. Breathe on lens; use a brand new cotton swab. If this does not work. a drop of Vodka on another brand new cotton swab. Drink remainder of vodka AFTER cleaning lens.
I have IA-type filters on almost all of my lenses. And I remove them whenever I intend to take pictures.
John, Mount Vernon, Virginia USA
Well :rolleyes: it's up to me to decide what "significant degradation" is when I use my lenses. Right? And to me any unnecessary degradation... and anything in the light path that increases the likelihood of flare etc.... is unacceptable.
Once I bought a really nice lens; the seller boasted that the thing had always been protected by a UV filter! Wonderful, right? Wrong. Turned out the damn filter -which had fingerprints on it- was stuck on there. I had to dremel it off, and it was basically impossible not to damage the lens threads while doing so (took much longer than an ordinary circumcision). Mind you, this is even more of an issue now with the plasticky lenses that easily crossthread. Buyers of "protective" filters beware: the solution can easily become the problem, and then what? Lenscaps are for when the lens isn't pointing at a subject; when the cap is off, just use a hood and be happy.
Anyway, back to glass cleaning theory...; ) surfactants micellize crud. That's why soap works in the shower. Water alone does not take off oil, and oil is what causes crud to stick so strongly that you cannot simply blow it off, so....
Accidental incursion of fluid into a lens is not an issue with MeOH and EtOH, assuming of course that it's done properly (by applying the solvent to a microfiber cloth, as people have suggested). These clean solvents have high vapour pressure and are gone almost instantly. They are readily available in purity levels high enough to leave no residue.
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I use a product from Freestyle called Eclipse Optical Cleaning System along with PEC Pads, and it's far and away the best I've ever used. This stuff is amazing for getting all the final marks, film, oil, whatever off the glass. I've cleaned old Cooke and Dagor lenses that I thought were fogged and they turned out looking like new.
I used to think Kodak lens cleaner was good, but this stuff makes Kodak lens cleaner look like crap. It contains Methanol which is a nasty very flammable solvent - don't smoke around it. However, you're only using a couple of drops at a time so it shouldn't be at all hazardous (just be careful not to get it in your eyes or drink it).
Now - I'm assuming that since this is made for optical cleaning that it won't harm the coatings on modern day lenses. I've used it on old uncoated lenses and new coated ones with equal results. I highly recommend it.
I've tried many of the suggestions above and I've never achieved satisfactory results. I prefer simply replacing the lens cap as often as possible.
For me it is the Eclipse Optical System and PEC pads. This works the best IMHO. One thing I have found is that if the lens has finger prints/oil you need to use a few pads, don't keep using the same pad. Wet it wipe it replace it and repeat.
I to try to keep the hood and cap on as much as possible, but there are always the times like---looking at a scene and reaching to take the lens cap off only to realize that it is already off and now you have a few nice finger prints on your filter. Oh yea I always use filters--good ones.
Last edited by 23mjm; 02-24-2009 at 12:47 AM. Click to view previous post history.
Reason: can't spell worth poohhhhhh
Originally Posted by keithwms
... And it is up to ME ... when I use mine ... etc., etc.
Zounds!! This PROVES that you and I are different!! - Although it seems apparent that no proof was necessary in the first place.
... And to me any
unnecessary degradation... and anything in the light path that increases the likelihood of flare etc.... is unacceptable.
Sad!! There is a method with a prick (not attempting to be funny re: the "circumcision" reference) or center punch and a jewelers hammer - envision the mechanics of an impact driven screwdriver. A very gently driven impact screwdriver. MUCH gentleness!!!
... the damn filter -which had fingerprints on it- was stuck on there. I had to dremel it off, and it was basically impossible not to damage the lens threads while doing so ...
With patience, that has never failed me.
As to the Dremeled filter threads - Are they a great loss? I don't suppose you would use them anyway.
An interesting observation - but a solution for a problem I don't have ...
Anyway, back to glass cleaning theory...; ) surfactants micellize crud. That's why soap works in the shower. Water alone does not take off oil, and oil is what causes crud to stick so strongly that you cannot simply blow it off, so...
Ed Sukach, FFP.
At the Earl's Court Broadcast Video Expo last week, I came across a firm (True Lens Services) who specialise in repair and maintenance of lenses. In an FAQ on a handout, one question was of course "How do I clean the glass?" Answer: "Better still, don't get it dirty in the first place! But if you do, start by using a puffer bulb to blow away as much debris as possible without touching the glass. Then gently use a camel-hair brush, starting in the centre moving in circles towards the outer edge. When there is no evidence of dust or dirt, use a lens cleaning tissue with an appropriate cleaning chemical."
I'd add to that a) as has already been said, a lot of surface debris can accumulate before becoming a problem, and usually then only when shooting into the light. b) when brushing the lens, hold it upside down so that debris falls away from the surface rather than just being distributed over it. c) lens tissues have never impressed me - they are usually too hard and crinkly to follow the surface of the lens without excessive pressure. I prefer Tomosy's approach of using a plain soft, facial tissue, with just a bit of heavy breathing (!) on the lens unless any grease was involved.