Is lens fogging that big of a deal?

Discussion in 'Rangefinder Forum' started by Mark Fisher, Apr 30, 2011.

  1. Mark Fisher

    Mark Fisher Subscriber

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    I recently bought a very inexpensive 50mm Summicron DR. It does have some fogging, though. It isn't real bad, but it is obvious when you shine a light through it.
    If I am shooting BW, will it make a significant difference beyond some reduction in contrast? I'm happy to get it cleaned, but don't want to bother if if isn't necessary.

    Thanks -- Mark
     
  2. Tom Nutter

    Tom Nutter Member

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    You may get some extra lens flare occasionally, but who knows, you might also end up with a unique look, so if it works for you, then awesome!

    There's a chance also, that if you set the lens in the sun, some of that might clear up a little.
     
  3. budrichard

    budrichard Member

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    Any modification of the original lens specifications will result in degradation but the question is how much? Since you don't have a Mint DR for comparison, then the best you can do is use the lens and see if the results satisfy yourself which they probably will.
    Any repair to the lens is wasted money.-Dick
     
  4. mablo

    mablo Member

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    I clean most of my older rangefinder lenses by myself. Older rangefinder lenses are surprisingly easy to dismantle. All you need is a cheap spanner wrench (from *Bay), a cheap set of very small screwdrivers, lots of Q-tips and some lens cleaning fluid (from *Bay). Then just google for instructions or try rangefinder forum for more information.

    I recently had a slightly fogged old Canon 50mm/1.8 RF-lens. It was okayish when fogged but after 30min cleaning job it became a star performer.
     
  5. Ian Grant

    Ian Grant Subscriber

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    Any lens fog will have a marked impact on lens contrast, it doesn't take much before a lens is pretty much useless except for special effects. I have a Zeiss Ikonta & Novar that's unusable because of slight lens fog.

    Ian
     
  6. bwrules

    bwrules Member

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    For some, that special effect may be as useful as a primary lens. A friend shoots with a lens that has a completely scratched front element for low contrast and flare.
     
  7. R gould

    R gould Member

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    I have a Retina II which has slight fog,or something, and I wouldn't change it as it gives really lovely soft focus low contrast which work very well for the right subject, such as portraits of ladies, and I use it a lot, I suppose I could get the lens cleaned, but the images it creates are so nice that I prefer to keep it as it is,wonderfully sharp but slightly low in contrast, lovely
    Richard
     
  8. Mark Fisher

    Mark Fisher Subscriber

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    Thanks Ian, that is the answer I suspected. I've never had a fogged lens before so I wasn't sure. I tend to like nice, crisp images in the area that is meant to be in focus. Ah, well, simple enough to just send it out to get a cleaning.

    Thanks all -- Mark
     
  9. Ian Grant

    Ian Grant Subscriber

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    There's two basic types of lens fogging.

    The first is from the lubricants and is fairly easily cleaned, condensation can be similar in enlarger lenses depositing a fine dust haze.

    The second is more insidious and is caused by atmospheric pollution, some glass used by leitz and Zeiss in particular from somewhere around 1930 (new glass types used mainly for faster lenses) is soft, it's very prone to scratching and also atmospheric attack. Leitz Summars are very suscepible and also some Tessars - newer 1930 computations and only a few focal lengths and also Novars.

    So there's a situation where a 135mm/150mm Tessar from about 1930 (ish) and up to 1938/9 is prone to going soft but lenses before or after are fine.

    Leitz also had a problem with out gassing from the barrel lubricants leaving a deposit on internal elements, which only begins to show up years later. That may be the issue with your Summicron.

    Ian
     
  10. ic-racer

    ic-racer Member

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    I have had good success removing that fog. If you leave it there it will give low contrast images of high contrast scenes. Low contrast scenes should image OK.

    If there is damage to the coating, there is nothing you can do about that. So the bottom line is that if all the fog does not come off with GENTLE cleaning, it represents permanent damage to the coating and will not get any better no matter what you do (unless you own a coating maching). So don't go and scratch the lens with tough abrasive cleaning technique.

    http://www.largeformatphotography.info/forum/showthread.php?t=63370
     
  11. Ronald Moravec

    Ronald Moravec Member

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    I purchased a 50 3.5 Red Scale at a show without having the required penlight to do a test. I did hold it to a ceiling light and found nothing wrong. The very first roll showed the typical muddied tones of a fogged lens. Sharpness was not affected at this stage.

    I got my light and did an inspection. Sure enough, there was a very slight fog I could not see with the previous test.

    So off to get it cleaned. $75 later it is like new and has the sparkle I expect from a Leica lens.

    So water clear is the word if you want the true Leica look.
     
  12. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    In my experience, if you like the lens, then it's worth having cleaned. Internal haze and fogging reduces contrast, and it's fairly easy to remove, presuming the lens isn't hard to disassemble (modern zooms, complex wideangles, and lenses with floating elements can be quite difficult to disassemble). There is some risk involved, since it is always possible that an element can have a flaw that isn't apparent until the technician tries to reassemble the lens, tightens a ring that holds it in place, and it cracks. A good shop can also collimate the lens, making sure that the cells are all properly positioned upon reassembly.
     
  13. Mark Fisher

    Mark Fisher Subscriber

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    Well, I had it cleaned and it now sparkles. It was only $60 so it was well worth it.
     
  14. Diapositivo

    Diapositivo Subscriber

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    Mark, I'll probably never to to Chicago but, in the interest of present and future forum readers, I suggest you post the name/address of the technician who made the cleaning. Good repairers are not widespread and I think when one makes a good work it is good for everybody to know it.
     
  15. Mark Fisher

    Mark Fisher Subscriber

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    Youxin Ye.....he was fast and did a great job. He isn't in Chicago, but in the Boston area. Even at that, it was only 10 days including the mail.
     
  16. Xmas

    Xmas Member

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    Fogging can be bad, some of the Leica lenses and some of the Canon lenses used optical glasses prone to etching, by fogging.

    Best to inspect regular & clean immediately before damage occurs.

    I got Canon f/1.8 LTM, Canon f/2.8 LTM...

    Noel
     
  17. pricca

    pricca Member

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    Hy @mablo!

    I've just bought a beautiful Canon P (which is in need of some intervention) that came with that same also beautiful 50mm/1.8 LTM.

    [​IMG]

    Unfortuantely my lens has fog in one of the back elements.
    When you look at the front and back element, all good! When you do a "light test" things get worse...

    [​IMG]

    Could you be kind enough to describe roughly what is your method of cleaning after disassembling and types of fluid/tool that you use?

    Thank you so much for sharing.

    All the best
    Pedro
     

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  18. Xmas

    Xmas Member

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    There are two lens rings at the rear.
    The outer holds the optic in the heliciod .
    Undo with lens spanner carefully.
    The optics will drop out together with spacing ring.
    Some lenses are threaded so the front and rear will unscrew thin rubber gloves for purchase.
    If these lenses are not cleaned regular they will etch.

    My memory may be faulty way long ago, try google.
     
  19. pricca

    pricca Member

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    Thanks!

    Any recommendation on cleaning material ? Solution? (i.e. like what to avoid considering these are "older" lenses and thus might be more sensitive to today's typical cleaning agents?).

    Than you.
     
  20. Xmas

    Xmas Member

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    Your Canon had all surfaces hard coated so internals are just like external.

    Zippo lighter fluid
    Cotton wool waste
    new micro cloth to finish off

    It is possible to scratch the coating and glass with a bit of silica grit take care.
     
  21. pricca

    pricca Member

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    Thank you so much. That has been very informative.

    All the best,
    Pedro