[miks]

Took my da 50-200 to a 3 day trip with continuous light rain and strong winds. While doing my complete cleaning when I got home, I saw fungus growth on the front element.

My question is:

Can I disassemble the 50-200 and clean/sterilize that fungus area?

[Spock]

Unbelievable! I'd like to know why this stuff chooses to grow on optical glass - why not on the side of a tree or something!

I once bought a brand new FA28-70/4 and it had fungus out of the box! (It was of course immediately replaced under warranty).

What I'd really like to know is how do I prevent fungus taking root in my photographic gear? It must be possible to take some sort of preventative action?

PS - I'd take the WR to a professional to get it cleaned and disinfected. My understanding is they treat the lens in a fume hood with toluene or some such toxic chemical to kill off any remaining fungal spores.

[blende8]

A lens, exposed to high humidity, is like a greenhouse.

It looks like the border is slightly bent at the position of the fungus.

If you have an SMC Takumar 50/1.4 you could point its rear element close to the fungus and the Alpha radiation will kill the fungus.

Seriously, I agree that a professional cleaning is in order.

[bdery]

What I'd really like to know is how do I prevent fungus taking root in my photographic gear? It must be possible to take some sort of preventative action?

Yes : keep the lenses in a relatively dry area, avoid leaving water on your WR lens, and if you're worried, pack your gear with some silica gel.

PS - I'd take the WR to a professional to get it cleaned and disinfected. My understanding is they treat the lens in a fume hood with toluene or some such toxic chemical to kill off any remaining fungal spores.

I agree. Disassembling a lens is always tricky, with a WR lens even if you do things right you run the risk of messing up with the seals.

One thing that can be done is to expose the lens to direct sunlight for many hours / a few days. Sometimes it will help. Other times, saling it inside a ziploc bag with loads of silica gel will help too.

[Nachodog]

Is it me or does it feel like any WR lens should not even be able to develop fungus on the inside without the seals being compromised?

Shouldn't this be a manufacturing issue where Pentax is responsible for clean/repair?

[normhead]

The deal gentlemen is, it's Water Resistant, not water proof. I lost my first zoom lens to fungus. This was 30 years ago but at that time lenses were held in place by cardboard. There would be your tree mentioned above. I'm assuming because I don't know any better that plastic is all the rage these days, but, when I took this lens to my local camera repair guy, he said, once it has mold inside, it's toast. You can take them apart and repack them, but they are never the same. So you can take my 30 year old advice and do with it what you want. Once again, I'd be happy if someone comes on and says things are different now.

As for moisture and lenses, a guy on here recently went on about how his lens was still working after being out in bad weather. Well, it's not right after the bad weather you have to worry. It's after the mold has time to grow. My little colony wasn't visible until 3 months after the trip that killed it. Once that little bit of moisture gets inside, your lens is going to die. It's pretty much as simple as that.

SO as a canoe tripping bad weather kind of guy I've got a few words of advice." Optio W90".Waterproof, dustproof, shock proof , small and unobtrusive. ANd a few more words.... "Pelican Case." When the weather is bad, seal it up in a weather proof container. I can throw my pelican case off the side of my canoe, keep it outside the tent during thunderstorms, it doesn't matter. No matter what happens no water is going to get at my equipment. Thinking a plastic baggy was going to do the trick cost me my first digital camera. My rule is, if the weather is even moist, the camera goes in the case. If I do see a shot I have to have, it comes out briefly, then it gets inspected briefly for water spots on the barrel, fully extended, dried thoroughly, and then put back in the case.

If you're smart, you'll think of your WR lens the same way you think of your non-WR lenses. Think of them as subject to water damage, but with a better chance of survival than your normal lens. That's what you're paying for. But bottom line, lenses and water don't mix. Any time they come together there's risk. If you really have to shoot in the wet, and you can't take the easy way out, ( Optio W90) buy one of those water tight things the divers use. You have lots of choices. Exposing your WR lenses to water for more than a few seconds shouldn't be one of them.

Pelican Cases



See the orange box by my chair? That's got K100D, a 16-55 and a 70-300 in it, and it makes a great table or seat in a pinch. In this case my bear proof food barrel is sitting on it , because I was rummaging for a snack. But the picture was taken witn an Optio W10 (stolen from a launch point last summer). Because 90% of the time that's what I shoot with from my boat. If you can afford a DSLR, you can afford a pelican case to keep it dry.

[Nachodog]

I see what you're saying normhead, but if you're paying a premium for weather sealing, you should expect to be able to use your gear in most (reasonable) weather without fear of fungal growth.

If the standard results were that these DA* lenses were susceptible to fungus and moisture infiltration under non-storm/hurricane weather, we would definitely be hearing more instances of problems on these forums and certainly there would be a much larger outcry.

Of course this is just my opinion given without any first hand experience with WR lenses.

[séamuis]

from what I understand of all this stuff, is that the weather sealing can be a friend and a worst enemy. see, when the lens is sealed it helps prevent moisture from gaining access into both the lens and the body, but should moisture get in, the sealing makes it extremely difficult for the moisture to dry out. there was a similar story to this one on the forums before in regards to fungus growth, and the consensus is, that fungus and mold etc, is everywhere. its likely already in your lenses to begin with unless your lenses were manufactured and assembled inside environmentally controlled clean rooms. without sealing its easier for things to dry out. and as we all now, this stuff doesn’t grow in dry environments, it needs moisture. if you are using the equipment in less than desirable conditions with weather sealing, but say you change lenses, well now you have allowed moisture to get in. then you attach another sealed lens on the body and it stays there. well now you have a pretty darn good growing environment. se what im getting at? I have always been weary of these sealed lenses for this reason. I don’t know the circumstances of how the moisture got in, from the OP’s post but I feel pretty sure that the sealing didn’t help things. especially if the lens is always attached to the body. Im not so sure the seals were somehow ‘compromised’ or not either, but like I said, the weather sealing can be both a friend and enemy.

[v5planet]

This thread has turned largely to the true efficacy of seals and moisture getting inside of a lens. But the fungus on the OP's lens looks to me like it's growing on the external surface of the glass -- can the OP comment? If this is just a surface ailment why are we so worried about the lasting integrity of miks' lens?

[Nachodog]

Would this be fungus, what the right arrow points to?

I would say that what you have is worn optical coating, not fungus. Can anyone else confirm?

[séamuis]

I would say that what you have is worn optical coating, not fungus. Can anyone else confirm?

or a waterspot or cleaning mark, or a number of other things. that photo doesn’t look like any fungus growth I have seen before, but I cant really tell what it is.

[normhead]

if you're paying a premium for weather sealing, you should expect to be able to use your gear in most (reasonable) weather without fear of fungal growth.

I notice that my Optio w 90 says waterproof to 20 feet. That I expect to survive any weather. Are you really willing to risk and expensive piece of equipment, because you think it "should" work under the specs you yourself set for it. You might want to contact Pentax and ask them under what circumstances they'd replace a lens because of failed WR, before you do something stupid.

[séamuis]

ou might want to contact Pentax and ask them under what circumstances they'd replace a lens because of failed WR, before you do something stupid.

there is no evidence that I see of any failed WR. as my first post points out, a proper WR system can increase the chances of getting fungus under the right circumstances.

[macTak]

If you have an SMC Takumar 50/1.4 you could point its rear element close to the fungus and the Alpha radiation will kill the fungus.

No, you'll just create a mutant super-fungus . Alas, even these radioactive lenses grow fungus, so we are doomed.

As to the OP, I'm sorry to hear it. I can't speak to disassembly, but you should at least start by trying to kill the fungus with UV light (either from a UV lamp or the sun).

[sjwaldron]

Is that on the outside or inside?

Another reason I like having UV filters on my lens, so the front element has an additional seal for water to get through.