loneranger
Well-known
Just curious where the oil that is on some lens blades comes from. Howcome some old lenses have it and others dont. And does it have to be cleaned, will it cause some long term damage or it's just cosmetic.
wolves3012
Veteran
Usually comes out of the grease on the helical or some such place. Unless it's volatile and causes misting of the elements it's not usually considered a problem on an RF lens.
FallisPhoto
Veteran
1. There is no such thing as a lens blade. There are lenses, there are shutter blades and there are diaphragm blades and they are not the same thing.
2. oil on shutter blades: Oil does not stay where you put it. Given enough time, it will eventually creep onto any surface the original oiled part comes into contact with. Most factories use too much oil and grease, so eventually it gets everywhere. The lighter components of oil also evaporate and condense, and help to draw more oil into themselves, by dissolving the heavier elements. On shutter blades, as the oil strays onto the blades and dries up, it becomes sticky, very like road tar. The sticky tar-like deposits cause the blades to stick together, adversely effecting shutter speeds, or even freezing the shutter. This will usually not cause damage, but will have to be cleaned before the camera can be used again.
3. oil on diaphragm blades: Oil also causes diaphragm blades to stick together. Unfortunately, diaphragm blades can be forced, causing major damage.
4. oil on lenses: Usually, it condenses from inside the shutter, over many years. It should be cleaned; this is why: Opaque detritus on a lens usually won't have much effect on a photo. It blocks light, so it also blocks any negative effect it would have on the optical properties of the lens. It won't show up in photos because it is so far inside the minimum focusing distance that it is blurred into oblivion. Oil is transparent though. It lets light through, along with any negative effect the shape of the oil deposit has had on the optical properties of the lens. A transparent deposit on a lens, in effect, changes the shape of the lens surface. It also provides food for lens fungus, which can etch the glass and coatings of lenses.
5. Lighter fluid, a popular solvent among camera repair people, will dissolve most hardened lubricants almost instantly (the exception is Agfa's infamous green grease, which polymerizes over time and creates molecular chains of plastic).
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loneranger
Well-known
Vow, thorough answer, you sound like an oil expert.
David William White
Well-known
I have found more than one old folder with oil on the leaf shutter blades or iris blades as an attempt by the last owner to 'fix' them. What they find is that the oil takes a snappy shutter action and slooooows it down as the blades attempt to open/close against a viscous fluid.
Lighter fluid is used, but it has particulates. I've had better success with carb cleaner or throttle-body cleaner (as it's now called). Evaporates grease and leaves no residue.
Lighter fluid is used, but it has particulates. I've had better success with carb cleaner or throttle-body cleaner (as it's now called). Evaporates grease and leaves no residue.
FallisPhoto
Veteran
I ought to be. I've certainly cleaned enough of it!
FallisPhoto
Veteran
Some does, some doesn't. Ronsonol and the type of naptha you buy at hardware stores are pure naptha. Any particulates you find in them came from the camera.