Haze, cleaning marks, fungus, dust, scratches, bumps - oh my...

Discussion in 'Adapted Lenses' started by Sabre36, Jan 2, 2013.

  1. Sabre36

    Sabre36 TalkEmount Regular

    Dec 1, 2012
    Earlier, I've asked some beginner questions on using legacy lenses. I have now gone that route with a Rokkor 28mm 2.8, a Rokkor 50mm 1.7, and one AF/OSS lens, the new Sony 10-18. I find that I use the 50mm indoors, the 28mm for street photography, and the Sony - not so much yet. I just got back from a trip to Quebec City and found the 28mm the most versatile in walking around the old, narrow streets of that city. I want to add some additional legacy lenses to this mix - maybe a 35mm, a 50mm macro, and possibly a short zoom. I would also like to purchase some more expensive glass - Zeiss or Voigtlander - so I need a better gauge to figure out what I am buying.

    In buying lenses, I have found myself learning a whole new vocabulary - 'haze', 'cleaning marks', 'fungus', 'dust', 'scratches', 'bumps' - and wonder just how obvious are these problems? I think I can see obvious scratches and dust, but are the other problems truly obvious?

    Recently I came close to buying a Zeiss lens from Craigslist until the term 'cleaning marks' was revealed. I googled that previously unknown term, and it scared me off (obviously this is how I could afford this Zeiss lens in the first place).

    I am now looking at some Canon FD lenses, also via Craigslist. I have read that many of these lenses were prone to 'haze'. Is it obvious by looking through the lens from the rear into a light source?

    In buying lenses, I have done OK thus far just by going by the label, 'mint', which I'm guessing is pretty superficial. I'd appreciate any guidelines you guys can provide in purchasing used lenses (like use KEH).

    Thanks, Bob
  2. Jeff Spangle

    Jeff Spangle TalkEmount Rookie

    Sep 6, 2012
    Leicestershire, UK
  3. addieleman

    addieleman Passionate amateur Subscribing Member

    Nov 13, 2012
    Ad Dieleman
    Your list is a fairly complete overview of the problems you can have with a used lens :).
    Scratches: as shown in the story linked to by Jeff Spangle you can see that small scratches on the front elements are quite inconsequential. It's great for bargaining, but be aware that the resale value is significantly lower and selling is more difficult. If you're afraid of detrimental effects on image quality, you can blacken the scratches with a black marker, thus preventing undue reflections off a glistening scratch. Worked for me in a number of cases. Scratches on a rear element can have much more influence, you'll only want a few small scratches there.
    Fungus: mostly seen between glass elements within the lens. If prominent it's detrimental to image quality, it will increase flare and lower contrast. A lens with fungus is a deal-breaker for me, unless the problem is very small. Disassembling of the lens for cleaning out the fungus is rarely worth it and depending on the kind of fungus it leaves permanent damage on the affected glass elements.
    Haze: visible as a sort of misty deposition on one or more internal glass elements. If prominent it can be as detrimental as fungus. In principe haze can be cleaned, but only by disassembling the lens, which is a costly affair if you aren't able to do that yourself. Usually a deal-breaker for me.
    Cleaning marks: visible, mostly barely, as fine scratches on the front element. Inconsequential in mild form, it will lower contrast and increase flare when a part of the front lens looks matte. Scratches on the rear element mostly have more influence, so you'll want only a few small scratches there.
    Dust: there are almost always a few dust particles visible within the lens. Dust will become a problem (flare and lower contrast) when there is a layer on an internal element, but that is not so common. Ten or twenty visible dust particles have no influence on image quality.
    Bumps: mostly found on the front where they can prohibit mounting a filter and/or lens hood. Of course, a bump is an indication of impact on a lens which also could have caused a dislocation of one or more glass elements, leading to decentering. This decentering results in uneven sharpness across the frame, e.g. one corner sharper than the other. That said, I have a few lenses with some form of impact marks but they don't show visible decentering.
    Oil on the diaphragm leaves: lubricant can spill over to the diaphragm leaves, causing them to open and close slowly. For an adapted lens this doesn't have to be a problem if the diaphragm will close and open within a reasonable time frame, because the aperture is set manually anyway. It doesn't have to close and reopen in a fraction of a second like in a (D)SLR. At times I've used it as a bargaining argument; check it by operating the diaphragm pin in the bayonet mount. Most sellers quote normal behaviour as "snappy".
    Damaged bayonet mount: look for burrs, scratches or bent flanges on the bayonet mount, these indicate that the lens has been dropped while on a camera or was handled roughly. Decentering is the most probable negative influence on image quality.
    Focussing/zooming: must be smooth, without play. Excessive play can cause loss of sharpness. While gripping the bayonet mount I try to move the front ring, there should be only little play. Stiff focussing isn't really a problem, unless it came from dropping the lens, then threads could have been damaged.. Zoom action can be very loose, this is inconvenient but doesn't do any harm usually.

    And now it's time for other members to chime in, reporting on their misery with old lenses ;).
  4. SRHEdD

    SRHEdD TalkEmount Veteran

    Nov 25, 2012
    Viera, Florida, USA
    One of the 18-55s I got recently had a giant dust clot right in front of the rear element. I know we're supposed to accept that zooms get dust these days, but this one was WAY too big to look past. I sent it to Sony and had it back clean in a week, in-warranty.
  5. Jefenator

    Jefenator TalkEmount Top Veteran Subscribing Member

    Nov 23, 2012
    Oregon, USA
    Great link - TFS!

    I am often surprised at how a good lens will continue to perform well, even after being somewhat compromised. I got a Canon 50/1.4 with some visibly weird stuff going on underneath the front element. But it still tests out very well - go figure.

    Overall, I'd say make sure any flaws in the glass are reflected in the price, then go for it and have fun!
  6. WoodWorks

    WoodWorks Super Moderator Subscribing Member

    Dec 12, 2012
    Ashland, OR, USA
    The only time I've ever noticed any kinds of specks or other flaws on the front elements of some of my lenses has been when I've had them stopped WAAAAAYYY down, well past their diffraction limits.

  7. davect01

    davect01 Super Moderator Subscribing Member

    Aug 20, 2011
    Fountain Hills, AZ
    nice definitions page.
  8. Luckypenguin

    Luckypenguin TalkEmount Regular

    Sep 26, 2012
    Brisbane, Australia
    The presence of oil on the aperture blades may also lead to the oil transferring onto the adjacent glass elements. I have seen this happen on a Vivitar lens before.
  9. kevistopheles

    kevistopheles TalkEmount All-Pro

    Jun 18, 2012
    You'd be surprised what won't have an effect on the image. I bought a PL45 at one point that had a hair (looked like an eyelash hair) on one of the internal elements. It had zero effect in image quality. The seller was up front and told me before I bought it but the price was right and it was never an issue.
  10. Nubster

    Nubster TalkEmount Veteran

    Jan 5, 2013
    West Virginia, USA
    What are the chances of this happening? I'm looking at a great condition Minolta MD 135 f/2.8 at a bargain price but the description says slight bit of oil starting to show on the blades.

    This is quoted from the description "Aperture blades moving good, but has some little signs of oil."
  11. Bimjo

    Bimjo Super Moderator Subscribing Member

    Oct 28, 2011
    Washington State
    If you take the normal precaution of not leaving your camera gear in the trunk of the car in mid-summer it probably won't be a problem. Like most lubricants, the lube on aperture blades gets thinner at higher temps, so reducing the time it spends at those temps, or actually reducing those high temps goes a long way toward alleviating the problem.