Condensation question

[uplander]

Tonight after work the Goldfinches were at the thistles in the horse pasture so I grabbeb the 40D and 400 f/2.8 on a monopod and headed out. The camera and lens were in the house all day and outside it was close to 90 and very very humid. As I looked through the viewfinder the first time I was confused as the lens would not focus and had a momentary heart stoppage as realised the lens was fogged. Thankfully it was just the outside of the main objective lens and after a few minutes when the lens hood off in the breeze it cleared up.

But this got me thinking . What is going on inside the camera with this heat and himidity change? Is this something I should be aware of and is condesation happening inside of the camera?

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[tirediron]

The condensation is caused by the hot, humid air hitting the cold glass (your front element). Since it doesn't actually directly hit the inside of the camera, there's much less 'fog'. I'm currently working in the Middle East, and in areas with temperatures of 130+ and humidity levels of 98-100%. As long as I leave the lens on the body when I first take it outside, and let it acclimate for 15-20 minutes, it's fine. Very little indication of any moisture inside the body.

Just don't change/remove lenses or rear caps for the first few minutes and all will be good.

[Easy_Target]

I've never had the lens fog up during hot humid weather before. I've had it fog up before though. I was shooting outside in about 20 degree (fahrenheit) weather with a windchill making it feel about 10 degrees for about 2 hours. I was outside and the lens fogged up despite being acclimated to the cold.

I'm guessing the air inside the lens that got chilled by the cold weather reacted to the heat from my fingers that passed through the outer shell of the lens itself. Even after I stopped handling the lens (it was impossible to shoot anything through that lens) it took close to four hours for it to unfog.

[Emerana]

Here in Houston, any time you plan to shoot in the warm months (it is VERY humid here) you have to plan to let it sit for a bit. Its the cool glass+humid warm air. I think inside all is fine, the fogging is on the outside

[Iron Flatline]

You'll find out the hard way, as I did. Take some pics and see if you spots on your images. Shoot a well-lit white wall (or better, the sky) at f/11 or smaller. I had one of the first dSLRs (Canon D60) and my sensor got some serious condensation - I walked out into the hot Miami sun, and changed lenses... NOT smart. Learned a lot about sensors that weekend... and the only way to get it "fixed" was to send it to Canon. There were no cleaning kits "back in the day".

[Mike_E]

Take a hard look at your lens too.

I found a product by Nikon at B&H that is supposed to keep condensation off of the lens but I have yet to stress test it. I would never try it on the sensor though (nor was it recommended for that).

[Big Mike]

Condensation can and will form on any surface that is cold enough to cause the water vapor in the air to condense. The cameras are closed up but they are not air tight...so some warm moist air can get into them.

To avoid the condensation, it's best to let the gear warm up before it is exposed to the humidity. One way would be to seal it up in a plastic bag before you bring it out. Even leaving it in a camera bag for a while, can help...but I've found that camera bags are pretty good insulators and it takes a while for the gear to warm up.

I've had similar problems when I was in Costa Rica...but up here, I'm usually having the opposite problem. If I shoot outside in the winter, I need to watch for condensation when I come inside.