Yellow Oil on Lens Mount

[gabriel_roca]

Hello all,

 

Very quick question: about a year ago I purchased a used but 100%

mint 50mm Summicron M. It operates flawlessly however, every couple

of weeks I'll take the lens off of my M6 and notice a thin layer of

yellow oil (not much) on the camera body's lens mount. There is NO

oil on the aperture blades (this lens is only a few years old). Any

ideas as to what could be causeing this? I've searched through the

threads but the only ones I find concern oil on aperture blades.

Essentially, I'm trying to find out why this is happening and wether

I should send it in for repair (seeing as how this does not at all

affect picture quality, etc.

 

Many many thanks and my best to you all.

 

-Ed

[henry_ting2]

The yellow oil is the aging of the grease. This happens over time after countless mounting/dismounting of the lens in high humidity environment. The condensed moisture mixes with grease and changes the molecule. In low Rh environment, the moisture generally evaporates and the grease never liquifies, but gets dry instead. That's why high humidity not only encourages fungus and molding of the lens, but effects the lubricants as well. Over time, the oil you see does get evaporated, but the consequence is that it hazes the lens too. I researched on this subject quite substantially and will be writing some text on this subject as well as recommending some fixes to preserve our expensive Leica gears ---- watch this space in the coming future.

[gabriel_roca]

Hello Henry,

 

I've heard of this theory (breakdown of the grease) before and it sounds very plausible. However, this lens is at most, six years old (judging from the serial number which is: 3862865. It would seem to me that a lens as young as this would not be suffering from the same sort of ailments that much older lenses tend to suffer from. Very strange, isn't it???

 

Thanks very much for your reply!

 

Cheers,

 

-Ed

[henry_ting2]

Which part of the world you live in. If its in the southern part of the U.S., the environment will cause it. I worked in Singapore once for 2 years and due to the high Rh, all my lens had this problem.

[gabriel_roca]

Hello again,

 

I live in New York but, perhaps in its past life (before I purchased it), the lens was in a different environment.

 

-Ed

[jay_.]

First of all Leica lenses use a lot less "grease" than just about any other brand I can think of. Second of all, the modern OEM lube is designed not to liquefy in temperatures in excess of 100F. It is possible, since this is a used lens, that someone before you squirted some non-OEM substance into the helicoid in order to smooth it out, and that is what is causing the leakage you describe. In fact, on older lenses even repairpeople sometimes work *a drop* of light machine oil into the helicoids to re-emulsify dried grease.

[gabriel_roca]

Thank you both very much for your input. The next question would be: is this dangerouse as far as the well-being of the lens is concerned? The deposit is rather light and takes a couple of weeks to acrue enough to the point where I deem it necesary to wipe it off. What do you think?

 

Thanks again,

 

-Ed

[jay_.]

I think you should rack the lens out to the close focusing end, then take a Q-tip and swab the exposed helicoids carefully. If doing that a couple of times doesn't stop the outpouring of juices, I'd surely have the lens professionally relubed by someone reputable such as DAG.

[roger_michel]

many a used lens is prepped for sale through the liberal application of light oil to the helical. i am sure if you opened up this lens (very easy to do actually), you would find too much oil in the threads. often a mint used lens is mint because it was never used much. these tend to stiffen up and the oil brings them back to life. the stuff will eventually stop seeping out. if it really bugs you. you can take a lint free, clean cloth to the exposed threads of the helical every once and a while. a gentle wipe should sop up the oil that works its way down before it has a chance to travel to the mount. this should cure the problem. time, as with many things, is the other cure.

[albert_smith]

If I understand your question correctly, this is oil at the lens mount (which is also migrating to the body's mount). if so, then here is one possible answer.<P>

 

I have only bought one new lens, which is the 90mm Elmarit M. In the book that came with it, under the heading, <B>"Tips for lens care"</B>, there is a mention of the use of a film of grease on the bayonet, which is applied at the factory. It also mentions that if needed, the user can re-apply the lubricant by applying a small amount of Vaseline with a finger and then following-up with a clean cloth. The warning to not use too much vasiline is under a bold font note.<P>

 

It is possible that someone previous to you may have did the self re-application and used too much, or didn't clean the excess as per the instructions. If the oil / grease is on the actual mount and not migrating there from some other part of the lens, you might just clean it up, and re-lube it as per the instruction sheet procedures.

[skeeter]

what henry, jay, roger, albert said. nice thread .