Advice on cleaning a slr lens

Discussion in 'Digital Photography' started by Cabbit, Nov 18, 2010.

  1. Cabbit macrumors 68020

    Cabbit

    Joined:
    Jan 30, 2006
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    Scotland
    #1
    Hi i just got a canon 550d body and then popped into crap generator and grabbed a lens (Canon EF 35-70 f/3.5-4.5 A Macro Zoom Lens Japan, which i am told should work but have not tired it yet)

    Well as i was buying it a lot of finger prints got onto the glass, so i am wondering how best to clean it?
     
  2. Policar, Nov 18, 2010
    Last edited: Nov 18, 2010

    Policar macrumors 6502a

    Joined:
    Nov 21, 2004
    #2
    I usually use a blower (not compressed air) or clean soft brush to remove dust that might scratch the lens during cleaning and then clean prints in a circular motion (from the center) using a clean micro-fiber cloth. Modern multi-coated lenses seem to clean pretty easily this way. This is how I remove prints, generally, since I don't use UV filters (except rarely).

    If you've got a lot of gunk you need to clean off, you may want to use lens cleaning fluid, but I've found it's likely to leave messy streaks. I still use it when I have to, applying the same method as above. Don't use water or anything not approved for lens cleaning!
     
  3. Ruahrc macrumors 65816

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    Jun 9, 2009
    #3
    What's wrong with water? Clean distilled water a very effective cleaning agent as it is a pretty strong solvent.

    Fingerprints are oil, so you'll likely need some kind of cleaning fluid (like an alcohol) or use something like a lenspen that has a graphite-based cleaner that absorbs the oils up.
     
  4. Policar macrumors 6502a

    Joined:
    Nov 21, 2004
    #4
    Distilled water is okay in theory; regular water can leave smudges. Water doesn't bond to oil, though, so it's fairly useless with fingerprints.

    I'm not sure I'd trust too strong a solvent on multi-coated glass. Alcohol is probably fine for occasional cleanings, but I've heard stories of excessive use breaking down lens coatings. Tiffen's lens cleaning solution is mostly water and ammonium carbonate. No idea why.

    I swear by microfiber cloth. I'll douse my cheap lenses in lens cleaning fluid and they usually clean up great with maybe slightly cleaning marks, but my fancy ones never get liquid near them, at least never intentionally. If a microfiber cloth doesn't remove finger prints (which it almost always will), then maybe go for lens cleaning fluid or distilled water (applied to optical tissue, not directly to the lens). I'm unfamiliar with the lenspen but it looks like a good option, too.
     
  5. Ruahrc macrumors 65816

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    Jun 9, 2009
    #5
    I've heard a lot of stories too, but never seen any proof. Truth is that lens coatings are a lot more durable than you might think and while they are not indestructible, it is quite difficult to chemically etch them from the surface of the glass unless you're using exceptionally strong solvents or acids, neither of which are that accessible to the average person.

    You'd have to be cleaning your lens a lot (and I mean truly, a lot) to wear off the coatings via solvation or abrasion from a soft cloth. Most of the danger of using strong or improper solvents (like acetone) is that it will melt the plastic lens housings if you allow it to touch them, putting the cleaner right on the lens and having it seep inside, or not cleaning any dirt/abrasives from the glass surface before wiping and then scratching through the coatings when you wipe.

    I have found the most success with methanol. It absorbs both polar and nonpolar contaminants effectively, and seems to wipe/dry without streaks better than other alcohol solutions I have tried.

    Ruahrc
     
  6. Policar macrumors 6502a

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    Nov 21, 2004
    #6
    Makes sense. Didn't mean to argue and I'll keep methanol in mind next time tiffen lens cleaner doesn't work. I've just found microfiber cloth does the job surprisingly well with fingerprints.
     
  7. Cabbit thread starter macrumors 68020

    Cabbit

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    Jan 30, 2006
    Location:
    Scotland
  8. jabbott macrumors 6502

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    Nov 23, 2009
    #8
    Lens Pen all the way. I used to use microfiber cloth but it was always difficult to keep the cloth dust-free. The lens pen is specifically designed to remove finger smudges and dust and in my experience it does great at both. The only problem I've had is that it doesn't work 100% on Hoya coated UV filters. It's more like 80% effective for those.
     
  9. Ruahrc, Nov 19, 2010
    Last edited: Nov 19, 2010

    Ruahrc macrumors 65816

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    Jun 9, 2009
    #9
    Policar,

    I didn't mean to come across as disparaging your suggestions, and I apologize. I was trying to offer some counterpoints- particularly the one about rubbing off the coatings, because as often as I have heard this advice I have yet to see any proof of someone who rubbed the coatings off his/her lens. I'd love to be proven wrong about this but personally I think it's an exaggeration.

    Microfiber cloths work great for the occasional smudge, but if it's more than just a small fingerprint I have personally found that liquid cleaning solution is needed as the microfiber cloth just ends up smudging the oil/dirt around the lens instead of lifting it off.

    Ruahrc
     

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