there are some lines on my summicron

[herrick_mak]

can anyone explain why there are some lines on the lens they aren't scratches

[koray_p]

This is looks like a lens element separation. It happens

when the cement holding two optical elements start

giving up due to age or a shock. There are people

repairing that kind of problem, with varying success.

 

K.

[SCL]

<p>If the lines you are referring to are the chromatic curves, that typically is separation of the elements refracting light. You need to have it professionally serviced.</p>

[herrick_mak]

holy cow this seems hard to fix???

[SCL]

<p>Depending on the situation it can be quite difficult, with no guarantee of success. Essentially from what I understand, the cement between elements needs to be dissolved and removed, hoping not to remove any coatings on the element itself. Assuming that part goes well, and there is no fungus which has gotten between the elements since the beginning of separation, the next part is reheating everything and applying a modern cement - and in doing so ensuring the elements are perfectly (and I emphasize the word perfectly) centered. Then the lens needs to be recollimated. This whole process is quite delicate, and could totally solve the issue or render the lens a writeoff. So, choose a well experienced pro in this field. not your local repairperson.</p>

[john_shriver]

<p>Focal Point Lens would be the place to send it. Not cheap, lens should be in perfect condition otherwise for it to make financial sense.<br>

(CRR Luton in the UK used to do this, but it's not clear if they do anymore.)<br>

If it's new enough, Leica would be able to repair it as well. They would probably replace the separated group, rather than re-cement it.</p>

[knut_schwinzer]

<p>Looks like a 50mm Summicron v4, right? They run around 800-1000 (put your fav currency), I think it would be an economical (almost) total loss if you would turn it in for a qualified repair. But: If the images look fine, and you asked just out of curiosity, keep calm, keep on clickin'! Many lenses with this kind of fault simply deliver perfect pictures!</p>

[Robin Smith]

<p>Agree with Knut. Are you happy with the pictures?</p>

[john_robison4]

<p>Yeah, what Knut and Robin said. Also, regarding repair, just curious but would not this be a less expensive fix just to replace the rear cemented group? That is, if Leica could furnish it as a replacement part.</p>

[Gus Lazzari]

<p>Hold your horses everybody !</p>

<p>Unless this can be viewed during a true "<a href="http://www.kenrockwell.com/tech/flashlight-test.htm">Flashlight Test</a>", you may just be seeing "birefringence" revealed by certain types of ambient lighting (simulating polarized light).</p>

<p>The lens glass when it's heated and then rapidly cooled, may have the surface of the glass cool much faster than the center of the glass, so it contracts. This can cause compressive stresses while the center of the glass expands because of its temperature (producing tensile stresses). Couple that to the multi-coatings and the optical quality adhesives, and this visual effect can be characterized as stressed birefringence...</p>

[herrick_mak]

<p>This is actually the old 35mm summicron v4 pre-asph! probably because i brought this to the alps....but the temperature difference wasnt that bad i thought. I have sent to Mr. Lin in taiwan and I saw his experiences in repairing separation of lenses and he also fixed few of the exact same summicron 35mm before. I will show you here all the photos I got after scanning the films. It doesnt happen in every single photo but sometimes it shows up as straight rainbow like lines on the right side of the photo.</p><div></div>

[Brian1664876441]

"Newton's Rings". The balsam between the elements in the group has separated. This is an expensive lens- best to have it

done professionally.

 

For a $15 Canon 135/3.5 LTM lens: I used index matching fluid as used on an oil immersion lens for a microscope. 10

years later, no signs of problems. In this case- the tight fit of the elements in the barrel held alignment and surface friction

held the lenses together.