[abruzzi]

I bought a A50/1.4 from KEH that arrived on Friday. A close look showed a bit of fungus around the perimeter and on darker spot with some fungus radiating from it maybe a half centimeter from the edge. It’s all on an element somewhere in the middle of the lens. I don’t know if it is big enough to affect images—probably not. The lens was listed as “bargain” quality, but for the price I wouldn’t have expected fungus. I haven’t found a clear listing of what is considered acceptable on a “bargain” lens. The other bargain lens I bought from them at the same time didn’t have anything on the optics.

I live in a dry desert climate, so it may not grow or spread, especially with the intensity of the sun around here. So I could keep it as is and not worry about it. Alternatively I could return it and eat the shipping cost. Finally, I could try cleaning it. I’ve never tried disassembling a lens, though I should have the tools necessary. I’d prefer to try first with a throw away lens, and I have no idea how complex that particular lens is, and what element needs cleaning.

I’m currently leaning towards returning it, or if they do exchanges, exchanging it for an “excellent” A50/1.7 that is a little less than I paid for the 1.4. I just don’t like the idea of something that could potentially spread. Am I right to be freaked out by lens fungus?

[Adam]

I bought a A50/1.4 from KEH that arrived on Friday. A close look showed a bit of fungus around the perimeter and on darker spot with some fungus radiating from it maybe a half centimeter from the edge. It’s all on an element somewhere in the middle of the lens. I don’t know if it is big enough to affect images—probably not. The lens was listed as “bargain” quality, but for the price I wouldn’t have expected fungus. I haven’t found a clear listing of what is considered acceptable on a “bargain” lens. The other bargain lens I bought from them at the same time didn’t have anything on the optics.

I live in a dry desert climate, so it may not grow or spread, especially with the intensity of the sun around here. So I could keep it as is and not worry about it. Alternatively I could return it and eat the shipping cost. Finally, I could try cleaning it. I’ve never tried disassembling a lens, though I should have the tools necessary. I’d prefer to try first with a throw away lens, and I have no idea how complex that particular lens is, and what element needs cleaning.

I’m currently leaning towards returning it, or if they do exchanges, exchanging it for an “excellent” A50/1.7 that is a little less than I paid for the 1.4. I just don’t like the idea of something that could potentially spread. Am I right to be freaked out by lens fungus?

Am I right to be freaked out by lens fungus?

If it wasn't disclosed in the listing, yes. I would start by asking KEH if they would be willing to repair it. If not, return it and get something else, whether it be the 1.4 or 1.7 version of the lens.

[Bob 256]

Fungus usually is between two cemented lens elements so it's not nearly so simple as cleaning dust or oil from a lens surface. It involves separating the elements which can range from difficult to near impossible, cleaning, and then re-cementing them - a fairly daunting task (not counting the main lens disassembly to get to the element to begin with). Left alone, the fungus can stay about the same or it can grow, given the right conditions - not an entirely good prognosis for a lens.

I think Adam's suggestion is the best.

[dms]

I hav never had a problem asking them to pay the postage (and they did) when a lens was not working OK. I presume fungus (in a BGN lens) falls in this category.

[BigMackCam]

Fungus usually is between two cemented lens elements so it's not nearly so simple as cleaning dust or oil from a lens surface. It involves separating the elements which can range from difficult to near impossible, cleaning, and then re-cementing them - a fairly daunting task (not counting the main lens disassembly to get to the element to begin with).

With respect, I've yet to come across that, and I believe it's rarely the case. I've serviced a number of fungus-infested lenses, and all instances have been surface infestations on inner elements. It's not so difficult to deal with once you've dismantled the lens far enough to reach the affected element(s), however... getting to that stage can be challenging, depending on the lens. Of course, depending on the fungus, it may have etched the surface of the element(s) in question... which can still be improved by removing the fungus, but it will never be completely "right". It's worth taking a punt on an old, inexpensive lens, but for something like this, I agree with Adam... return it and get a different one

[stevebrot]

I bought a A50/1.4 from KEH that arrived on Friday. A close look showed a bit of fungus around the perimeter and on darker spot with some fungus radiating from it maybe a half centimeter from the edge.

The key word is KEH. If the condition was other than "ugly", contact them for a refund or repair.


Steve

[Eyewanders]

The key word is KEH. If the condition was other than "ugly", contact them for a refund or repair.

What Steve said. KEH is deeply reasonable and will no be problematic. Don't hold onto a fuzz-factory glass. A50/1.4s are not uncommon - find a better one. You live in a desert climate, sure, but I would assume that the humidity inside your home is at least tolerably "normal"... and that's all that is required. It may be glacially slow, or it may never, but it could.

[abruzzi]

I’ll give KEH a call today and see what they say. Thanks for the info.

[Theov39]

With respect, I've yet to come across that, and I believe it's rarely the case. I've serviced a number of fungus-infested lenses, and all instances have been surface infestations on inner elements. It's not so difficult to deal with once you've dismantled the lens far enough to reach the affected element(s), however... getting to that stage can be challenging, depending on the lens. Of course, depending on the fungus, it may have etched the surface of the element(s) in question... which can still be improved by removing the fungus, but it will never be completely "right". It's worth taking a punt on an old, inexpensive lens, but for something like this, I agree with Adam... return it and get a different one

Do you know if the Pentax SMC A 1.7 is an easy lens to clean? Mine has very slight fungus on the top element just below the filter ring and on the last element at the rear. It really isn't very bad so I could probably leave it but is there a risk it could infect my other lenses if kept together in a humidity dry cabinet?

[BigMackCam]

Do you know if the Pentax SMC A 1.7 is an easy lens to clean? Mine has very slight fungus on the top element just below the filter ring and on the last element at the rear. It really isn't very bad so I could probably leave it but is there a risk it could infect my other lenses if kept together in a humidity dry cabinet?

I haven't serviced this lens, but looking at photos of it online, it looks very straightforward to take out the front and rear elements. There's a video here that covers the A50/2 (which should be pretty much the same):

You Tube

You Tube

As for fungus from one lens cross-contaminating others... There are people who say it can, and those who say it can't, but I've yet to find a conclusive answer. I don't have any fungus infested lenses at present (at least, none that I know of ), but as a matter of precaution I wouldn't keep them with my other lenses, just in case.

[abruzzi]

well, KEH was very professional. prepaid return shipping. I'm exchanging it for a 1.7 in EX condition, plus a little refunded. I'd still like a 1.4 (or hell, a 1.2...) but at least my super program will have a 50 of some kind. Thanks again for the info. I do want to learn to disassemble and service lenses, but I'd prefer to learn on a $10 ugly 50/2.

[Eyewanders]

well, KEH was very professional. prepaid return shipping. I'm exchanging it for a 1.7 in EX condition, plus a little refunded. I'd still like a 1.4 (or hell, a 1.2...) but at least my super program will have a 50 of some kind. Thanks again for the info. I do want to learn to disassemble and service lenses, but I'd prefer to learn on a $10 ugly 50/2.

Glad you got it sorted - not surprising given KEH was the source. They're just generally great about that sort of stuff.
I only started delving into lenses in the last year or two - most of the older glass is really straight-forward.
You still have to approach things in a focused (pun intended manner) and keep track of everything, but fungus cleaning is often not too big of a deal.

I recently won a lot that included three pieces of Konica Hexanon glass that was all in near-pristine physical condition - really great. The trouble was the obvious reason it was so pristine was that it had all been stored in cases, but in an old padded camera bag and likely in a basement or somesuch at the owners Florida home. I've never seen lenses this nice that were this infested. Even the camera's interior was nasty - bits of mold on the deteriorated light seals and mirror foam. But it was 20 bucks for the lot so I didn't sweat it, though I did keep it all very separated from my other lenses. I've got the 28mm and 50mm pretty much sorted - only the 200mm remains which is a fair bit more complicated so I'm building up the courage to wade into that one.

A before/after shot.

[Theov39]

I haven't serviced this lens, but looking at photos of it online, it looks very straightforward to take out the front and rear elements. There's a video here that covers the A50/2 (which should be pretty much the same):

Pentax-A SMC 50mm f2 Disassembly - YouTube

As for fungus from one lens cross-contaminating others... There are people who say it can, and those who say it can't, but I've yet to find a conclusive answer. I don't have any fungus infested lenses at present (at least, none that I know of ), but as a matter of precaution I wouldn't keep them with my other lenses, just in case.

Thanks for the advice! Following the instructions I managed to open up and clean the fungus and general dirt from my Pentax-A 50 1.7 lens. It was relatively simple and the lens is like new now. Works perfect and focuses sharply.

On the hand, I got over-confident and took apart a recent Nikon AF 18-55 lens. Bad mistake. That lens has so many micro-sized parts in it including many small wires and cables. Unfortunately, a couple broke and I just could not get the lens back together. Any body care to buy some Nikon parts?

[ZombieArmy]

Just remember that most if not all fungus found in lenses are dead when you see them. The only reason they grew was because there was a temporary lease on life for them. There's fungal spores everywhere, and lenses in general are not very hospitable spots for them.

I got an A70-210 a while ago for 5 bucks on ebay with some fungus in it. Has been exactly the same since I got it and I use it with no ill effects to my other lenses.