Rear element scratch

Discussion in 'Miscellaneous Equipment' started by Krzys, Sep 15, 2009.

  1. Krzys

    Krzys Member

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    I keep hearing that a rear element scratch is much more horrific than a front element scratch. This sounds logical but does anybody have any first hand accounts about rear element scratches that they could share?

    From what I can find front element damage usually results in flare and loss of contrast/sharpness, if any impact at all. Rear element problems seem to get very vague. 50/50 opinions on running for your life or using it with no noticeable effect.
     
  2. Steve Smith

    Steve Smith Member

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    You could probably use it and not notice anything. Just to be safe, an old trick is to fill the scratch with something opaque like Indian ink so it doesn't pass any light.


    Steve.
     
  3. jfdupuis

    jfdupuis Member

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    I have a lens on which there is a scratch on the rear element. The scratch seems not that deep and probably affect only the coating. I did extensive testing to see if the picture quality was affected and I've not been able to see any degradation of the image.
     
  4. Stan160

    Stan160 Member

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    I've got an example of the legendary Nikkor 105mm f/2.5 with a cluster of marks/scratches on the rear element. I set one of my Nikon bodies up on a good tripod and took shots with the 105mm and my Nikkor 80-200 f/2.8 (itself a stunningly good performer, and this example in excellent condition with no marks or dirt on any element), zoom set so the viewfinder contents were the same as with the 105mm.

    Results, even of a detailed scene, were indistinguishable to my eye between the two lenses. Using a D70 body and viewing on the computer at 100% showed a very slight edge in sharpness and contrast in favour of the scratched 105mm.

    Don't worry about it!
     
  5. Steve Smith

    Steve Smith Member

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    You can get away with quite a lot. On another forum, someone posted an image and asked if anyone thought anything was wrong with it. A bit further down, he posted a picture of the front of the lens he took it with.... together with the smashed polarising filter which was fitted at the time.

    There were no signs of anything wrong in the actual image.

    Therefore, a few scratches or even air bubbles are not going to have much of an effect.


    Steve.
     
  6. Q.G.

    Q.G. Inactive

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    Rear element scratches tend to cast a shadow on the film.
    Front element scratches do not.

    Front elements scratches can be a nuissance because the edges reflect light. Which is why filling them in with helps.

    The edges of rear elements scratches could reflect light too, but filling them in does not help with the shadow problem.
     
  7. André E.C.

    André E.C. Member

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    Ditto!

    Rear element scratches are nasty and not welcome on your optics at all.
     
  8. Krzys

    Krzys Member

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    Logical, but just more rumors to me. Do you have any examples or first hand accounts of this problem?
     
  9. André E.C.

    André E.C. Member

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    If it is that logical, why do you need examples?:surprised:
    Do you have an old optic? Scratch it, test and see for yourself, as for examples, no I don't have, I do take care of my optics!:D
     
  10. Krzys

    Krzys Member

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    Because I am interested in seeing pictures or tests showing the ill effects or at least stories detailing them. There are some front element damage tests floating around, but no rear element.
     
  11. Ian Grant

    Ian Grant Subscriber

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    It's very rare for a rear element to get scratched, that's why your finding difficulty finding anything. If it does happen lenses get retired :D

    Ian
     
  12. rthomas

    rthomas Subscriber

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    There is a box full of random old 50mm, 135mm, and 80-200mm off-brand lenses (think JC Penney, seriously!) at Biggs Camera here in Charlotte... I'm tempted to go buy a few, scratch them up to varying degrees, and post the results...
     
  13. Krzys

    Krzys Member

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    Ian Grant, Hasselblad jam + quick fumble with the tool at a wedding?
     
  14. Ian Grant

    Ian Grant Subscriber

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    Insurance ?

    Ian
     
  15. Prest_400

    Prest_400 Member

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