Oil on enlarger lens blades
I recently bought an enlarger lens and it appears that there is oil on the aperture blades (actually, there's oil on just one blade).
I know that oil on camera lens blades is usually considered a precursor of bad things to come (stiff aperture, possible hazing, etc.). Is it also a problem in enlarger lenses?
I purchased an old enlarging lens (at least 30 years old) and it had a slight appearance of oil on the blades (all of them).. I have used it for over a year and it still works great, very smooth.
If my experience is anything like the rest, this means no worries..
I do believe it is true after my past reading that >putting< oil on blades is not a good thing to do, have no idea of the real implications of >finding< oil on lenses...
I am sure someone can help clarify!
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Yes, it is a possible problem if the oil should migrate to the lens surface.
If it were mine, I would remove the lens elements, and with the aperture blades closed completely as possible, soak both sides with lighter fluid or even acetone.
Work the aperture back and forth as the liquid evaporates. Then repeat the process. Leave the lenses out until the following day to eliminate the possibility of fumes affecting them.
This may not be the absolutely best method, but it has worked for me more than once.
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I bought the lens on a certain online auction site recently and received it in the mail today. It initially looked very clean (it was advertised as "like new in box") until I worked the aperture ring and noticed the oil on the blade.
I'm mulling over whether I should go through the hassle of contacting the seller about returning it (in my stupid haste I left positive feedback after doing an initial inspection of the lens but before noticing the oil).
In the alternative, I could try opening up the lens and cleaning it as Jim Noel suggests. That's something I've never done before and, frankly, I'm not exactly mechanically inclined. On the other hand, I didn't pay much for the lens, so it's no great loss if there are extra screws left over after I disassemble it and put it back together again.
Lesson learned about the perils of that certain online auction site, I guess.
If there is no oil on the lens itself, then don't worry. Oil is mainly a problem on SLRs, where the aperture blades have to move very quickly and oil slows that action. On an enlarger, or rangefinder for that matter, the only issue is potential migration, which tends to be very slow.
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Jim may well have a point, still my humble advice is to leave sleeping dogs to lie. A spot of what appears to be oil on one blade of the diaphragm does not suggest disassembly. If the lens is functioning well (that is the diaphragm operates smoothly and freely), and the lens is clean and fungus free, leave it be. Now should you need to clean the blades, Jim's advice is excellent. Be careful with acetone, though. Methanol, isopropanol, and ethanol are excellent cleaning agents that will not harm anything in your lens ... acetone isn't always so benign.
One concern that just came to mind is the effect of heat (from the enlarger) on the oil. I wonder how likely it is for the oil to evaporate, due to the heat, and deposit itself on the lens elements?
Originally Posted by DBP
Those points are well taken, Doug.
Originally Posted by Doug Thomson
As for whether or not it's oil, I'm pretty sure it is. I know that sometimes older lenses develop a high polish on some parts of the aperture blades that looks like oil (I have another enlarger lens that has that appearance). But this is definitely some kind of lubricant. Also, I've noticed a faint trace of lubricant on the ring surrounding the rear element of the lens. So my guess is that the seller applied a little oil to the lens and, perhaps, overdid it.
Dishwasher? Or is rust a bad thing?
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Despite oil on the aperture blades, I don't see any sign of haze on the 90mm Elgeet that came with my Solar 57, and I think it is at least forty years old. Unless you keep the enlarger on more than I can imagine, or have a darkroom hot enough to be a health hazard, I doubt the oil will evaporate and condense very fast. And if it does develop a haze, then you can still clean it and the aperture blades as suggested above.