Just coatings, nothing wrong, I believe. The thicknesses of single coats are on the order of light wavelengths, which is, I think, where this comes from.
That particular lens (Elmarit-R 135/2.8) is prone to a problem with separation between a pair of the internal elements. I formerly had a very similar 343**** serial number copy with exactly the same issue. This lens should be multicoated, so this is not a coatings issue, but the "glue" between two cemented elements slowly coming unstuck and causing colorful interference patterns from the new super-thin glass/air interface in the lens. I was never able to see any optical problems from the rainbow patch, though potentially it could lead to slightly lower contrast and additional flare.
Right! There's shouldn't be any dispersion on/in glass like that under normal circumstances. It's a kind of separation like Mendenhall is saying.
Separation doesn't usually show up in images even when it's pretty bad - even the white circular type. Because it's properties usually include transparency at non incidence angles. The wider the AOF however, the more prone it is to reducing some contrast so my observational (and tested) explanation may start to fall down when it's the front element/group of wide angle lenses which is suffering from such separation.
Mine is an older 246**** and luckily does not have this problem. We both have version 1 of 135/2.8 which has a doublet on 3rd and 4th elements. Version 2 has improved contrast at full aperture, but still incorporates a doublet on 2nd and 3rd elements.
The consensus has it that the elements have separated, so you might write to Leica USA and ask if a replacement is even still available. I suspect that the cost of repair woud exceed that of the entire lens.
These lenses are 30+ years old, and only gradually developing a little separation with small to zero impact on image quality. I suspect you can use the lens for a couple more decades as-is, and still get nearly the same image quality as new. Given that the 135/2.8 is not an especially collectible/expensive Leica R lens, I'd guess that service would cost considerably more than another used copy of the lens.
mpmendenhall wrote:
These lenses are 30+ years old, and only gradually developing a little separation with small to zero impact on image quality. I suspect you can use the lens for a couple more decades as-is, and still get nearly the same image quality as new. Given that the 135/2.8 is not an especially collectible/expensive Leica R lens, I'd guess that service would cost considerably more than another used copy of the lens.
j.liam wrote:
The consensus has it that the elements have separated, so you might write to Leica USA and ask if a replacement is even still available. I suspect that the cost of repair woud exceed that of the entire lens.
It is. Yesterday, I got a quote from Solms for my R 35/2 v1. It just needs lubrication on focus ring, and Leica is asking 272 euro for the job. BTW, I paid USD 300 for this lens in 2004. I've decided to send it to a local repair shop instead.
Well thanks all, the thing is that I just purchased a three pack, the 80 lux and 28 and this all together. I have really no need for the 135, not what I shoot, although it is one nice lens, great work and looks mint otherwise. But I had planed to get rid of it as it was a package deal.
The bad thing is that I am sure I have seen that somewhere. Now I have to figure out if it is one of my lenses. Hmm.