Oil inside lens... what's the damage?

[Don Simon]

Once bitten, twice shy, or so they say. Whoever 'they' are, they're wrong :lmao: because I'm still buying lenses of eBay, and they're still faulty .

This time I picked up a 35mm m42 lens which was not in great cosmetic condition but appeared to have clean glass. When it arrived I checked it over and it did seem to be pretty good optically. But when I held it up to a light I spotted a small patch of what looks like oil on an inner element. I'm assuming it's oil because although it's completely clear, if it was water I suspect it would have dried up. Anyway I was wondering if anyone has had a similar problem or knows how this would affect the lens' optical quality. It's only affecting a relatively small area on one side of the element, but I'm assuming the effect will still be noticeable. Also, can anyone suggest a way of cleaning it? My first thought is to seal it in a box with some packets of silicon gel, but I don't think that works with oil. Also I can't disassemble the lens because, as seems to be the case with every lens I have a problem with, the four screws at the back of the lens will not budge.

I think not noticing or mentioning this was an innocent mistake on the part of the seller, so I'm not going to hunt him down and wreak terrible vengeance (also the lens cost me £0.99 :mrgreen but obviously I'm still looking to make it work if possible. Any advice at all would be great. Thanks in advance!

 

[Lumix]

Before attempting to repair why not take a few shots with it. It may not have that much affect on the results.

 

[DocFrankenstein]

It'll probably flare more than it's supposed to. How much more I can't tell.

For a buck, it's might a be a good buy regardless, if that's the focal length you need - use it.

 

[Rob]

You've got two sensible options and one mad one. Option one: shoot with the lens and forget about it. Only you can say whether it's a problem to the shot or not. Option two: Get the lens professionally cleaned (likely to be in the £120-£380 region for a proper job). Option three: Try and take it apart yourself.

Option three is extremely likely to leave the lens worse than it started. It's pretty unlikely you've got the skills and the tools. It's also possible that you won't even be able to re-assemble it again!

The obvious advice is to shoot a roll and see what happens. Then make a decision about fixing it - you should be able to get a quotation pretty easily.

Rob

 

[Kent Frost]

If it is in fact oil, it sounds as if the aperture blades have been exposed to an exceptional amount of heat, causing the blade lube to run. If that is the case, you may have a bigger problem than just a spot on an element.

 

[Don Simon]

Hi again, thanks for all the replies. I don't think there's any major problem with the aperture blades as they don't seem to be sticky, slow or or inaccurate. I did manage to take off the outer part of the focusing ring (seems to be the only part that can be safely removed and replaced) and found quite a bit of oil under there. It looks to me like maybe someone tried to oil the lens and some got inside onto the glass. Btw Rob, which of those options was the mad one? Getting it professionally cleaned, right? :lmao: It's only a £1 lens after all. Still you're right, I won't try fixing it myself. I've taken a few shots with it so I'll just wait and see. Thanks again everyone for the advice.

 

[montresor]

120 to 380 pounds to do a lens up! Whew, that's pricey. I guess I was rather lucky -- I had a 1965 Koni-Omega 90mm Hexanon with sticky blades and slack springs -- original lube was whale oil which had turned to blubber in there I think -- got it overhauled by the US expert on KO repair, cleaned blades, new springs, elements realigned, etc., for $91. Excellent job too, though the guy's workload is plainly heavy, a considerable time elapsed before it came back; but it was indeed better than new.