What's this stuff on my lens??

[pphuang]

I recently acquired this lens, and noticed that there is some stuff long the edges of the inner elements, both just above the level of the blades looking from the front






and also a rim of stuff just above the level of the blades looking from the back.






It is not on the blades themselves, which look clean and move fine. Rather, its on a ledge or rim sitting on either side of the blades.

It almost looks like maybe paint or dried glue that's flaking off a bit.

Functionally, the lens works fine, and this doesn't seem to have any noticeable effect on the photos, but I may have this looked at if it is going to become a problem over time, since I like the lens and it wasn't very expensive.

Appreciate any thoughts or insight...

[HuubL]

Separation?

[RF-Addict]

It's called Schneideritis - Schneider Large Format lenses were famous for flaking paint inside the lens - as long as it was moderate it had no effect on the picture at all. Yours looks pretty severe though. Seems there are huge chunks coming off your lens. The lens might need professional cleaning.

[Brian Sweeney]

Paint flakes will move around when the lens is tapped. I had flaked paint chips inside a Voigtlander Prominent Nokton.

Hard to tell without having the lens close-up. If it looks like it is ON the optics, It could also be dried oil.

[pphuang]

The stuff doesn't seem to move around when I tap the lens. The lens is also surprisingly clean, without much internal dust at all. It does seem to be on an inner lens element both above and below the blades. Is it possible that this is dried oil on the lens? - forms a nice circle around the edge of the lens on the inner back element, more "stringy" looking aound the edges on the inner front element.

I wonder how easy this would be to clean? One of those things were you wonder if its worth bothering, since the lens is quite usable as is, and maybe not worth throwing money at something that's not so easy to clean up....

[Brian Sweeney]

It is not hard to clean if you have a spanner. I've taken apart the 35/2.8 Canon RF lens. Rear retaining ring holds the optics in the lens mount. Once out, the optics blocks come out with the spanner. Q-tips, lens cleaning paper, ammonia eyeglass cleaner will take off dried oil.

But, if it gives good results- use it unless you enjoy taking lenses apart.

[pphuang]

Originally Posted by Brian Sweeney

It is not hard to clean if you have a spanner. I've taken apart the 35/2.8 Canon RF lens. Rear retaining ring holds the optics in the lens mount. Once out, the optics blocks come out with the spanner. Q-tips, lens cleaning paper, ammonia eyeglass cleaner will take off dried oil.

But, if it gives good results- use it unless you enjoy taking lenses apart.

Thanks Brian. Probably will just leave well enough alone - I remember seeing that recent classified where somebody started to take a camera apart and ended up with a mess - sounds like something that would happen to me! Although it wasn't a very expensive lens, might be worth doing just for the experience...

[pphuang]

Originally Posted by Platon

So i'll guess the front and back (middle) lens group have separated. Sorry to say but the "whiteness" round the elements on the pics indicate on a separation.
And this old lens could have a long history.......its easy to drop a camera or a lens.

Yes, my fear as well. Only way to know for sure is to open it up, I guess...

[Symeon]

yes, old oil, sorry but you cant clean it really, the Leica people can...
regards