Condensation on lens whilst shooting star trails?

Hi all, after shooting star trails for a While last night, I got a lot condensation build up on the lens, even though I wiped the lens with a soft cloth, it still continued to build up... Any hints and tips on how to avoid this or is it just something you have to deal with when shooting into the sky at night?


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Before the shoot, you need to allow the camera and lens to get acclimated with the outside temperature. If it came from an air conditioned place then place it outside where it is much hotter, then you can expect this to happen.

It was on the tripod for a good 5 hours before the condensation started to form... I put it on the tripod at about 6pm, was shooting perfectly fine till about 1AM when the lens just got covered in condensation....


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Samsonite said:

It was on the tripod for a good 5 hours before the condensation started to form... I put it on the tripod at about 6pm, was shooting perfectly fine till about 1AM when the lens just got covered in condensation....


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Click to expand...

At that point then, it sounds like a weather thing...

Another way in which condensation occurs is on hard surfaces, such as during the
formation of dew. Water condensing on a
glass of ice water, or on the inside of windows during winter, is the result of
those glass surfaces' temperature cooling below the dewpoint of the air which is in
contact with them.

Pat in NH

Yep. It's like dew forming on furniture. I've done outdoor gigs where it forms on guitars and amps - a real mess. Not a lot you can do, to my knowledge.

I found a discussion here. Not a lot of answers, but the idea is to keep the lens warmer than ambient temperature. Keeping air moving over it will help as well - a mild battery operated fan. Perhaps even keeping a handkerchief over the lens body?

Yes, I have even had condensation while hiking,, and the lens was in zippered pockets. can be a real problem if the water gets into the lens elements, it will dry, but often leave water marks. Weather seal lens helps. I like the idea of a battery powered fan, on a separate tripod,, blowing across the setup.

The condensation will form on anything when the dew point gets within 2 or so degrees of the temperature. Unfortunately there is nothing you can do about it.

hi, the dew/condensation is normal to any of us that shoot astrophotography thru a telescope are well aware of the problem.the problem is not the adjustment of temp it is dew . we use what are called dew heaters to warm our focal surfaces (lenses primary secondary and eyepieces)

Hi Guys, Im Going camping again from Monday to Wednesday next week, this time im going to a campsite which has water and electricity readily available... I was hoping to shoot some more star trails, but am weary of dew forming on my Lens and camera again. This might seem like a crazy idea, but since keeping the lens warm seems to be the solution, do you recon I should ask my missus to bring her hair dryer, so that every couple of minutes I can blow warm air over the lens and camera to keep the temperature of the lens / camera above the ambient temperature?

Ive also thought of fitting a thick wooly sock over the lens (With a hole through the bottom ) to try insulate it....
​

Any feedback on the above suggestions, camping at the moment and hoping to shoot some trails tonight....


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Only one word of advice - "acclimate"

Edit - make that 3 words - acclimate and lens filters. Remove wet one, put dry one on and dry wet one....repeat.

How do you suggest I do that?


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Swap them out in between exposures. You are doing stacks and not a single exposure, right?

Yes stacks, swap what out?


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Just saw the edit, I don't have any clear filters, just an ND400, which wouldn't be any use at night.... It's currently 25 degrees, will drop to 18 to tonight, shall I leave the camera out of the bag from now?


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Well, the only thing that really matters is the lens element so pick up a couple inexpensive UV filters. No need to buy expensive filters for this project.

Good idea, think I will give the blow drier a try to see if keeping the whole setup warmer will help avoid dew/condensation, not continuous, but a blast every few minutes to keep the setup above the temperature of the surrounding air...


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No go tonight, so cloudy I can't even see the moon!


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You do not want to do star trails on a moonlit night. You need to wait until the moon goes down or until a new moon. Star trails don't work so good when the moon is out, too much light.