What's the deal with Oily Aperture blades?

[Tim Joy]

I'm looking at some used lenses that say they have some oil on the aperture blades. Does it matter? What does it do to the image, if anything?

 

[J.R. Hudson]

It shouldn't do anything to the image, it should just be lubrication, right ?

 

[cordvision]

it could vaporize and settle down on the glass elements....

 

[Ted Ramasola]

it means the lube for the threads that makes the twisting of focus smooth has leaked. What will happen at some time is it will make the blades stick, at worse, when you twist the aperture ring, the blades wont adjust.
you will have to twist it extremly and back to 'jerk' the blades loose.

be cautious with this lens.

Ted

 

[Tim Joy]

Thanks for the replies. I think I'll stay away from those lenses then.

I have a 135mm FD lense that has a stuck aperture, (luckily it's wide open) so if I work it good, it might un-stick?

Okay, I just tried that. didn't seem to work

Any other way to get the aperture working again?

 

[setarcos]

Oil on the iris blades means they are sticky and slow to close and open on a photo camera while taking pictures.
If you plan to use the lens on a 35mm adapter, no problem (as long as they still adjust the iris)