This is topic Cleaning of lens's in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.
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Posted by Stephen Jones (Member # 16) on 12-28-1999, 06:06 AM:
There are a lot of methods used to clean lens's, but which is the correct way and how often I have seen situations where they are lucky to be cleaned once a month.Myself I clean them once a day using Kodak lens cleaning solution or lens cleaning solution purchased from a optometrist office as this dose'nt leave a film cover over the surface,I apply this and wipe clean with lens cloths.I have been useing this method for number years with good results.------------------
Posted by Brad Miller (Member # 2) on 12-28-1999, 01:24 PM:
Put a couple of drops on the tissue and wipe the lens gently in circular motions. Then quickly re-wipe the lens with a dry tissue.
Posted by John Walsh (Member # 168) on 12-28-1999, 05:08 PM:
I've used lens brushes for many years, and found that there's very little need to clean with fluid and tissues. The tissue can be fairly hard on the bluing, and most times the dust can be brushed away.Where I use to work, I went about 3 years without using any fluid and tissues. I did finally need some only because oil got on the lens.
Posted by Aaron Sisemore (Member # 145) on 12-29-1999, 02:05 AM:
Agreed- I usually will not use a liquid cleaner on a lens unless the lens has oil or fingerprints on it. I usually leave them alone or use compressed air to remove any dust or non-liquid debris...Aaron
Posted by Mark Gulbrandsen (Member # 72) on 12-29-1999, 09:37 AM:
When I worked at Canon on TV camera lenses we used camel hair brushes to clean light dust off the surface of elements. The worst thing one can do is blow dust off a lens element with compressed air. This is the equivelent to sandblasting the lens surface!! If there is alot of dust that a brush can't remove(such as an old lens thats been sitting on the shelf for half a century)then use a small Kimwipe with plenty of lens cleaning fluid. At Canon we used 50% MEK and 50% pure isopropal alcohol(probably why my hair is falling out). Start at the center of the element and go in a spiral motion towards the outside edge of the element. Change Kimwipes very often to prevent scratching the coating, and keep them damp. We were taught never to clean a lens element dry. At the very least to breath on the lens element first.
Mark
Posted by Greg Mueller (Member # 17) on 01-05-2000, 08:48 AM:
Being an amateur astronomer, one learns to not mess with the optical surfaces. I'm sure these lenses have antireflective (etc) coatings, and constant chemical cleaning and rubbing really can't be to good for the lens surface. I've seen some telescope mirrors that were amazingly dirty and still worked just fine. When you consider the size of a speck of dust and how much that speck deteriorates the image, you can have a quite dirty appearing surface without much degradation. I would say the soft brush or compressed air is the best idea. Why not use a soft drink paper cup to act as a lense cover when they're not in use?
Posted by John Pytlak (Member # 331) on 01-05-2000, 09:11 AM:
I agree that using compressed air to clean a lens is NOT a good idea, as it may force debris into the lens. "House air" may sometimes have impurities such as oil from the compressor. Loose dust or debris is best removed with a soft "camel's hair" lens brush. Never wipe the lens with a dry cloth or tissue. If there is a fingerprint (shame on you 
) or oily deposit, use a very small amount of lens cleaning solution and untreated lens cleaning tissue to gently clean the lens surface, being careful not to get moisture into the lens itself. Lens caps are a good idea if you have them --- just remember to remove them before the show!Don't forget to keep the port glass spotless and haze-free --- it's as much a part of the projection optics as the lens and lamphouse.
The December 1999 issue of Kodak's publication "Film Notes for Reel People" has an article I wrote about "Conquering Contrast Killers", which discusses lens cleaning. It's on-line at:
http://www.kodak.com/US/en/motion/newsletters/reel/december99/pytlak.shtml
------------------
John Pytlak, Senior Technical Specialist
Worldwide Technical Services, Professional Motion Imaging
Research Labs, Building 69, Room 7419
Eastman Kodak Company
Rochester, NY 14650-1922 USA
Tel: 716-477-5325 Fax: 716-722-7243
Posted by Randy Stankey (Member # 64) on 01-05-2000, 04:19 PM:
I am one of those guys who doesn't clean lenses until they 'need it'. I believe it's better to have a few specks of dust on a lens than to have it scratched from too much (improper) cleaning. However, I am also one of those guys who will just instinctively grab a lens brush or cleaning solution and a tissue when I do notice that a lens 'needs it'.A lot of times I'll look at a lens and find it looking like somebody sneezed on it. That really gets my goat!