Lens separation

Discussion in 'Leica and Rangefinders' started by leslie_p., Jul 11, 2005.

  1. How can you tell if there is lens separation? Is it easy to detect and
    how much would it cost to get that fixed..roughly?. Thank you
  2. Leslie,

    I'm not sure that lens separation will appear differently on a Leica lens than separation on
    a large format lens such as a Rodenstock. Perhaps, someone else here will be able to tell

    On a Rodenstock lens... most of the delaminations I've experienced start from the
    perimeter and it has the appearance of "oil on water." There's a coloration where the
    separation is. And, if you look really, really carefully... you'll see a delineation or line of
    demarcation. If you can imagine putting a bit of glue between two pieces of glass and
    squishing it together... the demarcation line is where the glue line ends.

    Hopefully, I'm explaining it in a way that you can understand what I'm getting at.

    As for the cost to get it fixed... someone else is going to have to provide the answer to
    that question!

  3. A good fix is heat up the elements to about 150C for an hour or so and cool slowly. I have done this with a LF lens, just popped it on the domestic oven at 150C for a couple of hours, turned the oven off ant let it cool overnight worked a treat. Best to remove everything except the elements and their mount first at 150C the oils in the lens will migrate and vaporize all over the glass etc.
  4. I used that method once (temp was 250F) at the suggestion of an old-time camera repair guy, the lens hasn't re-separated yet and it's been probably 7 or 8 years.
  5. I've used Huw's method on a dreadful Summar that I got on eBay for $32 (as a kit). It was badly separated before, and afterwards it only had minor separation. Got rid of the ghost image in the lens. But the lens is still horribly bad. There are still brass filings trapped between the rear groups, and the rear element has been epoxied into place, it's retaining ring is mauled. (I got another water-clear Summar on eBay for $111, I love that one!)

    Also, Huw's method will only work with old lenses using Canada Balsam (very refined pine pitch, basically) as lens cement. Won't work at all with newer lenses using high-tech adhesives.

    In terms of whether it's worth the expense of having lens separation fixed, can you let us know what lens? For instance, it's not that hard to get a decent Summar, and almost any work on that lens is very expensive, since the elements are peened into the mount. So most repairs at that level on a Summar are economically silly.

    On the other hand, such serious repairs to a 50mm Summicron can be economically feasible, but it's not a sure thing.
  6. It was for a 35mm Summicron Lens..and the person selling it does not know much about lenses to describe anything other than scratches. So I wasn't sure if I could detect lens separation fairly easily once I see pics. Thanks for your responses.
  7. You need to see the lens. Often early separation appears as a white arc around part of the circumference of an internal lens element, and the arc can grow with time. If it is just a small arc at the periphery of an element, it will have no effect on lens performance and may remain the same way for may years. More (deeper) separation can appear as an area of iridescent sort of discoloration. You really need to look at the lens yourself to determine if there is separation. A few random pictures will probably not show much unless it is really significant.

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