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What is this on this lens?


A miller

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Just received this second hand. It was represented as "98% condition". What are the short white lines around the edge of the inner rim of the lens?

 

Lens separation? Something to be worried about? The lens otherwise seems to be in great shape, and focusing well wide open at close range.

 

If it is a problem, any sense of how much it would cost to fix?

 

Thanks for you help.

 

Adam

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It's impossible to be sure without taking the lens apart... But...

 

Usually the sides of the glass elements and groups are painted black to prevent reflections when fitted into place in the barrel. Sometimes this paint separates from the glass, and you get these reflections. To repair- the optics need to be removed and the sides painted. I've used a black sharpie for older, less expensive lenses.

 

Try some test shots, something this minor should make no visible difference. If you paid a premium for this lens to be 98% perfect, it's not and you would be within your rights to return it. The defect should have been mentioned on a "98% Perfect lens". More like 98% except some minor separation of the anti-reflective paint. AGAIN- my best guess from looking at the pictures. My 28/2.8 Elmarit is an E49, slightly lower SN than yours, shows no signs of the reflections I see in yours.

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Thank you very much for your insights and expertise.

 

Here are some better photos. The one long and one short white lines seem to be reproduced three times. Given that the length of each mark is consistent with each reproduction, is it fair to say that the two farther into the barrel are reproductions/reflections of the first?

 

Do these better photos provide a better sense of what the problem is?

 

The seller of the lens has agreed to issue me a partial refund of $400. This would make the all-in cost of the lens $1100. Does this sound like a good price given this problem??

 

Many thanks again.

 

Adam

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Edited by A miller
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Again- best guess from pictures, the inner lines appear to be reflections of the set of lines on the outer element. The bright-spots are on the outer edge, very thin. I've had worse on lenses never show up.

 

$400 should more than cover a CLA on the lens if you decide to get one. Try a few shots with the lens to be happy with the results, I would keep it and accept the partial refund.

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Post #3 2nd picture shows a partial segment of a baffle or other lens mounting component. It is not uniform around the periphery of the front element. That would suggest to me evidence of partial or full dismantling in the past with inaccurate re-assembly. For peace of mind I would get the lens serviced.

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You have a mild case of 'Schneideritis', a common problem where the black paint edging the lens elements comes away through age or when servicing. On Schneider lenses at least it seems to make no difference at all to the optical performance, some people think that rather than to stop reflections it is simply cosmetic anyway. But still, with a Schneider lens it is cause for the price to go down a bit, so possibly the same with a Leica lens.

 

Steve

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It looks to me like the black paint surrounding the edge of the front of the front element has come off. The question is why? It may just be age and usage or it might be corrosion of the underlying aluminium. If the rest of the lens is clean with no signs of moisture damage (fungus or haze) then its probably age and use related paint flaking which will have little, if any, impact on images. (FWIW my 21mm (Schneider) Super-Angulon has mild Schneideritis and this seems to have no effect on the images it takes).

 

I'd give the lens a really close inspection (led torch to shine through the elements - some dust and perhaps marginal haze is to be expected, but no fungus and significant haze) to see if its been damp. Lastly, but importantly, check servicing and spares availability on this lens with Leica or reputable repairers to make sure that it can be serviced if needed. (I bought a 28mm Leica M lens some time ago which was cheap, but not as described (front assembly loose) and upon checking was deemed uneconomic to repair due to parts problems. It was sent back accordingly and I was refunded)

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This is simply air bells forming where the glass meets the black paint and metal of the lens barrel. Technically, a form of separation, but not nearly as bad a thing as true separation of glass-to-glass cemented elements.

 

Similar to seeing air trapped beneath ice - the differences in refractive index give the "white" effect.

 

http://s.imwx.com/common/articles/images/201305/12_wiggett_icebubblesFIX_650x366.jpg

 

Usually, this has no practical effect on the images, since the lens barrel metal is still opaque underneath and none of this area is image-producing. It is possible that in just the right (or wrong) lighting there might be some reflection from the white areas back into the forward lens elements and then into the image path.

 

However, that fact that three different elements are affected in exactly the same place (circumferential-wise) makes me wonder if a mild impact casued the separation, and may have had other less noticeable effects.

 

Regardless - the fix would be taking the lens apart element by element and refreshing the mounting cement. And checking for any less obvious problems.

 

Push it to extremes - try some shots directly and almost-directly into the sun, and see if you see any flares or other image defects that correspond to the location of the marks.

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I agree with wda David. Someone turned it loose and couldn't get some ring in the right place; it's not centered. As far as I can see from these photo's.

Edited by otto.f
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I really appreciate everyone's time and thoughts.

 

The concave nature of the lens seems to be the cause of the unevenness of the setting of the inner rim. When I hold the lens flat in a certain way, the inner rims all sync up and seem proportionate. When I tilt the lens and look down, the inner rims look out of sync; and this distortion changes every time I tilt the lens in a different direction. Don't know what this means, and I tried to obtain a reference point from my other Leica lenses, but none are built like this one.

 

The one thing that seems clear to me is the the long and shot line are being reproduced down the inner barrel through a reflection. Pics 3 and 4 show the second and third instances of the long and short line going in different directions; one slanting down to the left and the other slanting down to the right. It would seem to me that, if this wasn't a reflection, at a minimum the reproductions in both pics should be slanting in the same direction.

 

I have taken a look a the other version IV lenses on sale on eBay right now and they all seem to show the same phenomenon, at least to my untrained eyes.

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It looks entirely external to me ...... and the 1st photo suggests no decentering ......

 

... everything else is internal reflections.

 

If it works fine and takes images that are sharp evenly across the photo then do nothing at that price.

 

Being cavalier and reckless I would probably paint the offending area or go over it with an OHP transparency pen and see if all the reflections vanish........ and then spend ages trying to get marks off the lens element and probably remove the coating and scratch it in the process (oh yes.... I've done all this in the past trying to return perfectly serviceable lenses back to cosmetically mint condition .....:rolleyes:)

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Thanks again, all. I'll put a few rolls through it (hopefully tomorrow) and give it a whirl. At $1100 it seems that even if servicing is required, I'll still come out ok.

 

[Thighslapper - you made me laugh hard :) )

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