coating rubbed off on front of lens

Discussion in 'Native Lenses' started by broncophil, Mar 24, 2013.

  1. broncophil

    broncophil Mu-43 Veteran

    243
    May 23, 2010
    oh oh.. i noticed black "oil slick" like spot on then front of my lens. not sure what it was... i rubbed it, and it got bigger.. so i just did what any rational person would do. kept rubbing..

    it seems i rubbed off a "coating" of the lens?

    what does this do? probably some sort of flare protection?

    its 10pm so i have not had a chance to test it..

    needless to say, i'm bummed.
     
  2. BLT

    BLT Mu-43 Regular

    187
    Jan 13, 2013
    London
    James
    What lens is it, what did you use to rub it?
     
  3. mattia

    mattia Mu-43 Hall of Famer

    May 3, 2012
    The Netherlands
    Not that it helps you much, but use things like a lens pen and minimal to no pressure when cleaning lenses. First brush large particles off and then wipe clean as needed. Although I gotta say I'm surprised, coatings on modern glass tend to be pretty damn tough.
     
  4. speedandstyle

    speedandstyle Mu-43 Hall of Famer

    Unless you were rubbing with a coarse cloth or sandpaper I can't see the coating coming off that easy. There is a possibility of chemical contamination that caused the coating to react. After you "cleaned" it does the lens work?
     
  5. dwig

    dwig Mu-43 Top Veteran

    624
    Jun 26, 2010
    Key West FL
    +1

    It's vastly more likely that the spot is some oily substance on top of the coating. If this substance has a higher refractive index than the top layer of the coating then it will give the appearance more similar to uncoated glass and thus look like a spot with no coating.

    The thing to do is to properly clean the lens with a proper lens cleaning solution. My preference is a moderately dilute, ~50%, solution of ethyl alcohol/
     
  6. PaulGiz

    PaulGiz Mu-43 Veteran

    231
    Jan 3, 2013
    Rhode Island, USA
    Probably an oily fingerprint that you've smudged and spread over the lens.

    Use proper lens cleaning cloth and solution. If you don't have solution, first try distilled water (lightly damped cloth). As stated above, a bit of alcohol (diluted with distilled water) can help, followed by distilled water, then light dry polish.

    Odds are, you'll be fine.

    P.
     
  7. mattia

    mattia Mu-43 Hall of Famer

    May 3, 2012
    The Netherlands
    Uh, no. I never use 'protection' filters unless there's flying sand around, and never will. All they can do is negatively impact image quality, and the occasional wipe down is not going to damage the glass.
     
  8. teddoman

    teddoman Mu-43 Regular

    191
    Mar 22, 2013
    nyc
    That's what happens to my eyeglasses after using a micro fiber cloth on them every day. I would tend to guess you rubbed off a coating. Though I'm surprised it can happen so quickly.
     
  9. speedandstyle

    speedandstyle Mu-43 Hall of Famer

    I have been doing photography for many years and cleaned a lot of lenses. I have never had the coatings come off from proper cleaning{or even improper in my early days}. I have seen lenses with scratches in the coatings but never where the coatings just rubbed off. I have heard of coatings pealing or flaking off when exposed to corrosive agents{including heavy smog}.
     
  10. jloden

    jloden Mu-43 Hall of Famer

    May 15, 2012
    Hunterdon County, NJ
    Jay
    I'm with the others, unless you had a really coarse or abrasive cleaning cloth, more likely you had a fingerprint or other oily substance you've spread around the lens. It happens, and it does look like a coating smudge (I've been freaked out before by a finger mark that looked like a coating scratch).

    I'd try a wet cleaning, or another option I've had good success with is using a lens pen and a little warm breath to loosen any dirt and oil. Don't panic :smile:
     
  11. broncophil

    broncophil Mu-43 Veteran

    243
    May 23, 2010
    the lens is a 14 2.5, and for sure the coating has rubbed off.. in the center it is now super clear, and the edges where i could not get the cloth in enough, the coating is still there.. i' not sure what got on there, but whatver it was, it sure did a number.

    i still have not had time to test it, but i'm keeping my fingers crossed.... if i needed a reason to get the 12 or new 17. i guess this is it.
     
  12. kwalsh

    kwalsh Mu-43 Top Veteran

    775
    Mar 3, 2012
    Baltimore, MD
    I've never seen a coating come off without using some sort of solvent. That said, if it is the front of the front lens element it should have minimal impact unless you put a filter on the front of the lens (at which point you risk flare from the un-coated front element). The back of the lens is a different story... you really want that coating.
     
  13. WT21

    WT21 Mu-43 Hall of Famer

    Feb 19, 2010
    Boston
    Picture of the spot, please (of the lens itself, not through the lens)
     
  14. usayit

    usayit Mu-43 Hall of Famer

    What lens is it?

    Modern coatings are fairly hard.

    Older lenses coatings are a totally different story.


    [EDIT]

    Ah.. saw the later post. That's really strange... its highly unlikely modern coatings can be rubbed off that easily. Defect? Pic's would be interesting.
     
  15. aonavy

    aonavy Mu-43 Regular

    143
    Nov 25, 2012
    Epping NH
    George
    yep, then lens is junk. Ill be it for half half :)