[Compaan]

Hi WR equipment owners,


True, I live in a pretty humid environment in southern Bahia state, Brazil and so as I upgraded a few months ago from the K-10 to the K-5, I decided to get myself a WR lens: the 18-135. Although I do not use it very often, I always keep it on the camera when I am not shooting, just to protect the combination as a whole. I never shoot in rain or expose my equipment to humidity in other way than I would have done with non WR equipment. I was sure things where pretty safe. Sure until yesterday.
I first picked up my camera after a 2 week rain period, and when I took it out of my photo bag (made of non humidity absorbing and accumulating material), everything seemed in order, however, when I attempted to see through the viewfinder what I intended to photograph, I got a rather “foggy world” impression. First I thought that it were humidity on the outside of the viewfinder, but after some analysis and finally taking of the lens, I discovered that the problem was on the inside of the 18–135 WR. Wow, what a disillusion!
After half a minute of sun on the lens, the water droplets quickly started to appear, completely covering the inside of the back element of the lens. A few minutes later they disappeared from the back element, having moved to the second element (the only other element I was able to observe). Well, end of the story: after a few hours of sun and breeze, the lens seems to be miraculously clean again. However, the lesson was awakening: Weather Resistant the lens is probably more in terms of not letting out humidity than of letting it in. I have never seen that much moisture inside any lens, and have seen some since I moved to Brazil.
If the environment in which I live is too humid for a WR lens/camera combination, I should maybe move to the Sahara to make the equipment work properly then, or is my lens an individual WR failure? Or is my camera? Because the K-5, on which the lens was stuck, is of course also full of humidity. WR; just a marketing thing after all?

[vonBaloney]

Sounds like you are dealing with condensation. Nothing to do with weather sealing.

[VoiceOfReason]

I would have it checked out because there are those members here who take thiesr into the shower to clean them up! You may have a not-so-good copy there.

[Compaan]

Sounds like you are dealing with condensation. Nothing to do with weather sealing.

Condensation is definitely a problem I have, and would it have been on the outside it wouldn't have bothered me. The problem is that it is on the inside, and that to me seems to be a clear lack of sealing.... Or am I wrong here?

[Compaan]

I would have it checked out because there are those members here who take thiesr into the shower to clean them up! You may have a not-so-good copy there.

If you are right, I am less unhappy. At least it would mean that there is nothing fundamentally wrong with the concept, only with individual peaces perhaps.

[vonBaloney]

Condensation is definitely a problem I have, and would it have been on the outside it wouldn't have bothered me. The problem is that it is on the inside, and that to me seems to be a clear lack of sealing.... Or am I wrong here?

Yes. It is quite common for it to occur inside lenses. Sealing has nothing to do with it -- there is air in there. So you probably had a cool, dry camera/lens (maybe even air-conditioned) and then you took it out into the heat and humidity -- bang, instant condensation. If you want to avoid this, let the bag heat up in the sun (closed) for a while before opening. I've also heard it suggested to keep the camera in a ziplock bag and then when you bring it out into the heat (still closed) you'll get condensation, but it should be mainly on the bag and not the inside of the camera/lens itself. If you are moving from air-conditioning to high heat and humidity, that is the worst situation, but any cool/dry to warm/humid change is a possibility. Most of the time there is no lingering effect -- just make sure once it fogs up you leave it in the heat long enough for it to clear up...

[Compaan]

Yes. It is quite common for it to occur inside lenses. Sealing has nothing to do with it -- there is air in there. So you probably had a cool, dry camera/lens (maybe even air-conditioned) and then you took it out into the heat and humidity -- bang, instant condensation. If you want to avoid this, let the bag heat up in the sun (closed) for a while before opening. I've also heard it suggested to keep the camera in a ziplock bag and then when you bring it out into the heat (still closed) you'll get condensation, but it should be mainly on the inside of the bag and not the inside of the camera/lens itself. If you are moving from air-conditioning to high heat and humidity, that is the worst situation, but any cool/dry to warm/humid change is a possibility. Most of the time there is no lingering effect -- just make sure once it fogs up you leave it in the heat long enough for it to clear up...

Thank you very much for your great explanations! Maybe things are not that bad after all. As I understand through your words: because there is air inside the lens, in consequence there is also water inside the lens. Which means that the higher the environments air-humidity, the more water there is inside the lens over time....

Well, I am a bit more at ease. Again, thank you very much for your time and willingness to enlighten my case!

[vonBaloney]

Is it possible WR actually does make it worse? Not by *not* keeping out humidity, but by slowing down the transfer of heat/air with the outside? We'll need a Mr. Wizard to puzzle that one.

Anyway, here you go with a longer explanation:

The Science of Lens Condensation

[climit]

It is true that weather sealing makes the lens more vulnerable to condensation. It shall happen on rare occasions.

[VisualDarkness]

Well, the weather sealing probably acts as a thermos by keeping the cold air inside and not mixing it with the outer temperature, therefore keeping the lens cool longer. Ziplock bag works great for transporting the lens from cold to hot air as the condensation happens on the outside of the bag instead of inside the lens while heating up.

Cold air hold less humidity than hot air so when the hot humid air comes in contact with the cold lens the air drops water as it cools down, sadly on the cold lens. But when locking the cold air inside the ziplock bag you create a barrier with the dry cool air so the lens never get exposed to the dropping of humidity, when the hot air cools down, that instead occurs on the bag.

[Tonto]

Echo what others have said, condensation still happens with my K7, especially in humid countries- solution, the plastic bag trick.

[SuperK5]

Some people say they take their cameras all apart when they store them with the lens and body separated. Perhaps if you are going to store your camera with a lens on it be sure to make it one that is not WR. That may let the camera breath a little better over time with barometric pressure and humidity changes.

Also you may try getting some desiccant packs to put inside a sealed camera bag. I always save the ones that come with the stuff I buy.
http://www.widgetco.com/desiccant-packs?

[disya2]

Agree with SuperK5. WR thing is not working if you store your lens non-attached to the body. In my experience 18-135 + k-5 stands very good against condensation if the lens was attached in dry warm place before going out.

[jatrax]

Any zoom lens, WR or not exchanges air with the outside world every time you zoom in or out. So if you are shooting outside in a humid environment you will draw in air that has the same humidity level as the outside air. As long as the lens / camera is the same temperature as ambient there is no problem. But if the camera / lens is significantly cooler than ambient, the warm humid air being drawn in WILL condense onto the inside of the camera / lens. Worse case is taking your gear from air conditioning (either car or building) into a warm humid environment. If you want to test this, put your eyeglasses or anything else glass in the refrigerator, when they are cold go outside into a warm humid environment and they will fog up. Same thing happens to the lens elements.

The same thing can happen in cold climates if you are outside in cold weather and go into a warm humid house or building, you get the same effect.

Best advice is to warm up your gear to ambient in as dry a place as possible. One solution, assuming a cool or air conditioned house is a "dry box" this can be something as simple as a small cabinet with a light bulb inside to keep it warm. If your gear is already warm when you go outside then there is no condensation. The dry box also serves to "drive off" any humidity that is in your gear when you come inside so in tropical climates it is a good idea. It also helps prevent fungus from growing in your lenses, though that is not as much of a problem with newer lenses as it was with older ones.

I recently visited Columbia and after a stay of about a hour in a very air conditioned shop walked outside again. My lens immediately fogged up, outside and inside and it was maybe 20 minutes in 100 degree F temperature before it un-fogged enough to be usable.