Oil on Aperture Blades

[chip j]

I have about 8 lenses of various makes that have a little oil on the aperture blades. Some of them have been sitting around for 20yrs because they're a $100 problem each. When is it safe/not safe to use them? Thanks, Chip

 

[Alan W]

SLR lenses can be hampered by this oil problem more than rangefinder lenses.I've got a Cannon screwmount that has more than a little oil on the blades and have never had a problem because the blades are set without having to be activated by the camera.In SLR lenses the aperture has to stop down quickly and then retract,oil can impede this action-It depends on how much oil you've got on them,really.Put the lens on the camera and watch it.

 

[clayne]

Yep, if the lens is capable of stopping down from f/16 to wide-open quickly, I wouldn't worry about it. It's mainly an issue when the oil gets between the blades and the surface tension prevents the lens from stopping down quickly and/or stopping down erratically. Depending on the lens, the fix is usually breaking down the 2 halves to get to the iris and then cleaning the blades with naphtha. Also depending on the iris mechanism it's either quick and easy or a pain in the ass because one has to mark where certain set screws were such that the iris is calibrated right and f/16 is not f/8 or f/64 afterward.

 

[mgb74]

Most of the time, when I've encountered this, it's not that big an issue. Unless really bad, the oil doesn't effect stopping down, it just slows up the opening back up. I just make sure I don't advance and take another shot too quickly. Of course if really bad, it may not open back up at all.

 

[Gerald C Koch]

Cleaning the aperture blades is really a job for a professional. They are very thin and delicate and damage easily. Then too they must be replaced in the same positions that they held originally in order to work correctly. The job becomes more and more difficult with larger numbers of blades.

 

[clayne]

Cleaning aperture blades is actually not that difficult at all, nor is reassembling them. Obviously a quick digi-snap beforehand is a good idea, but really they only work in one way. Use a tweezer to move them around by their guide pins. What can get difficult is alignment of the iris cam itself - but that depends on manufacturer.

 

[Bill Burk]

The one time it becomes a catastrophe is when there are drops and these land on a lens surface. Then the oil can damage the coating if left too long.

I had a camera where this happened twice. The first time, was when I got the camera and I had the lens polished professionally. The second time the problem appeared I was not interested in having it polished again, so I sold the camera on eBay (with really, really, clear disclosure of the defect) and it became another person's problem.

Here is what oil on lens damage looks like:

 

[chip j]

Thanks,everyone. Where does tis oil come from and how doe it get loose? My lenses mostly sit in a drawer & get little use, I have so many.

 

[gone]

The oil is just lubricant that gets dislodged over the years. As others have said, on a rangefinder it's not a big deal (and seldom a big deal on an SLR either unless the oil has thickened and is slowing the blades down). You just want to keep an eye on the glass because the oil may migrate over time to the lens surfaces. Cleaning the blades is seldom a big deal either. Usually, all that is needed is unscrewing a lens element and gently cleaning them w/ a Q-tip w/ some lighter fluid on it. You swab w/ a wet one, and then wipe w/ a dry one. Repeat as necessary. What may look like an oily finish on the blades after that will often look nice and clean after the lens sits over night.

 

[ambaker]

I noticed oil on the blades of a Russian lens, after it was stored face down in a drawer, for about a year.

No migration to the glass, so far, and blades are nice and smooth.

This is not an automatic lens, so you have to stop down, to get your metering done correctly.

I won't be opening it up. It's a Tair 11a. 20 blades is well beyond my first timer skills.


Sent from my iPad using Tapatalk HD

 

[trythis]

If you are going to try and clean them yourself, take a bajillion photos, but hopefully someone online has already done it. The oil on mine always seems to come from helical grease that works its way to the blades.
One problem I have doing this is that they always seem to fall out all over the place and it can be hard to figure out which side the washers go on.