p.1 #1 · Correct pricing for lens with slight fungus?
Hi, I've come across a local Canon 500mm f4.5 L @ $1800
However, upon inspection one of the rear elements has two small colonies of fungus that look like spiderwebs that cover what I would estimate at least 10% of that specific element.
The exterior of the lens has numerous slight scruff marks on the white paint with exposed black, the hood has numerous marks, and the hood-end of the lens has a slight dent where it is evident it was dropped (I didn't examine if the hood would go on, come to think of it. Let's assume the hood goes on with no issues)
There is no box, nor case. Just the lens, the leather cap, back cap and hood.
What would the correct pricing be in this case?
Would it be possible to have a local (or Canon) camera center clean the fungus out? If so, how much would this cost?
p.1 #4 · Correct pricing for lens with slight fungus?
so you are saying there is no way to decisively rid of it?
I am assuming I can ask a camera center if they can clean it up.
I took a couple sample images and they look fine, so the current state isn't terrible. All I have to do is halt the growth by killing it for sure and possibly rid of it for sure with a cleansing
p.1 #5 · Correct pricing for lens with slight fungus?
and then ask a camera center if they can clean it up.
I suggest you pose the "Can you clean it?" question to your camera shop before you buy the lens. Chances are they will say they can't do anything about it. I think that is Canon's response when customers bring fungus-contaminated lenses into their service centers.
p.1 #6 · Correct pricing for lens with slight fungus?
If I was willing to buy a lens that is obsolete according to Canon and a lens that has virtually zero spare parts available, and if the USM breaks, it is junk...
I sure wouldn't waste $1,800 on it.
Another $1,200 or so, you can get one that looks like new... with the same service concerns, but you are starting from a better position.
If you really want that one with the mushrooms, I'd offer $500.
Canon will not touch that lens simply because it is obsolete. Fungus or not. Roberts had a really rare and expensive Olympus lens with fungus for sale as-is not too long ago, so they didn't want to mess with that one.
Finding someone else to mess with it... who knows. (Virtually) No parts are available, so if something breaks during disassembly, you are SOL.
p.1 #7 · Correct pricing for lens with slight fungus?
You're assuming that the fungus is only on the lens elements. What about the the IS and AF components that you can not see without disassembling the lens? Lets assume the hood goes on with no issues. But lets also assume there is fungus on the IS and AF parts as well. Seems like a high risk to me.
p.1 #8 · Correct pricing for lens with slight fungus?
Konablue wrote:
You're assuming that the fungus is only on the lens elements. What about the the IS and AF components that you can not see without disassembling the lens? Lets assume the hood goes on with no issues. But lets also assume there is fungus on the IS and AF parts as well. Seems like a high risk to me.
p.1 #10 · Correct pricing for lens with slight fungus?
Yup, speaking personally the correct price for a lens with fungus is "0". I wouldn't touch it, and i definitely wouldn't let it near my camera or other lenses.
p.1 #11 · Correct pricing for lens with slight fungus?
Ignoring the fungus for a moment, it sounds like it's in Bargain to Excellent-minus [E-] condition at best, and so I expect it's worth about $2000, max. With fungus, it's worth considerably less. I would not buy it, unless I knew of a local shop that could tear it down and have a look at it, before I commit to buy. I'd ask the seller to split the cost for this service.
I've attached an optical diagram for the 500/4.5L. The two rear-most elements are in a group, and so it's possible that the fungus is in the cement between the elements. If this is the case, then you'd have to replace the group to get rid of it. Also, have you pulled the drop-in filter to check it?
BTW, I've had about a dozen lenses with fungus that either developed after I bought them or that I bought without noticing it. All of these were older "Alt" lenses. I've never met an EF lens with fungus. (Now, I store my lenses in a dry cabinet.) Anyway, about half of those lenses were successfully cleaned by my local camera repair centre (ave. about $75 a pop), and the other half were thrown out. You really can't tell if it can be cleaned successfully until it's opened up on the bench.
p.1 #12 · Correct pricing for lens with slight fungus?
The problem with fungus is you don't know if it has damaged the glass already or not. You also don't know how thorough a clean will be to get rid of it and don't have it spreading again after a few months. So basically you don't know what the damage is until you've opened it as said above.
If you really really want it you could ask the shop to send it for clean and service and *if* it comes back nice and clean you pay them the $1800 plus whatever they paid for the service.
Personally though I wouldn't touch anything with fungus even if it was given to me for free. Ok maybe I would but the first thing would be to send it for a clean.
p.1 #13 · Correct pricing for lens with slight fungus?
Luis Fraga ("Fraga") had a major problem with EF lens element fungus, and he probably has ample experience with its removal. Wouldn't hurt to get in touch with him for additional info if needed.
I would not get such lens even it were free, nor would I accept any components that came from the lens.
p.1 #18 · Correct pricing for lens with slight fungus?
Thanks for the advice everyone.
On thing I still don't understand is why none of you addressed UV dosing to kill the fungus.
I have a bio-hood at my workplace and it's likely equipped with a UVC lamp, since it needs to kill microorganisms.
Wouldn't this be an effective way to sterilize the lens? I understand that the fungus can grow on the barrel as well, but even some of that will get UV (although not all of it) and the small remainder of fungus can never outgrow its small territory as long as I periodically UV-dose my lens overnight.
This, and the fact that I doubt the fungus can grow to the point where it disables/hampers AF under these conditions, leads me to think that although it is unwise to buy the lens at $1800, it is a great deal for $500 or so.
p.1 #19 · Correct pricing for lens with slight fungus?
kabraxcis wrote:
Thanks for the advice everyone.
On thing I still don't understand is why none of you addressed UV dosing to kill the fungus.
Maybe it's because you didn't ask how to handle it, only how much it's worth.
UV can kill the fungus, but not remove its residue and/or damage. The real problems occur when the fungus etches through element surface multicoatings and/or leaves tracks in the cement between grouped elements. You can't determine if this is the case until you open up the lens. The closer to the rear of the lens it gets, the more pronounced will be any possible effects on optical quality.
Here's a compendium of FM links on fungus in lenses,
p.1 #20 · Correct pricing for lens with slight fungus?
I'm in the boat of buying it if it was less than 1800. I'd probably buy it for around $1000 or less,if everything seemed to work great. I used to work in a lab with a bio safety cabinet with uv light as well, however they're not always dependable unless you switch them out regularly and also in case of contamination, I would not want to jeopardize my or my colleagues work. However, being in San Diego with little humidity, fungus spreading/growing isn't really a worry for me. I would just quarantine the lens. I have read there are spores everywhere, it's just if the conditions allow them to grow or not.
