Yashica 55mm f4 ML Macro Repair

[Hatchetman]

Very interesting thread. Where does all this oil come from in old lenses?

[ic-racer]

Very interesting thread. Where does all this oil come from in old lenses?

The grease on the helicoids. Even though grease is traditionally composed of long chain alkanes, stuck together with hydrogen bonds, some of the molecules escape to the air. Lenses with with extensive helicoids, like zoom lenses and macro lenses can be more susceptible to this.