Lenses fogging when sun hits

[Harley Goldman]

On my last couple of backpacks, I have been out shooting early morning when the sun was low and behind ridges. The mornings were brisk, probably in the upper 30's to mid 40's. As soon as the sun cleared the ridges, the temperature went up by 25-30 degrees and my lenses immediate fogged, front and rear elements. It took a while holding the lens in the sun to defog it. Short of drilling vent holes in my bellows, any suggestions on how to prevent this type of fogging? The defogging delay cost me a couple of nice shots.

[Steve Hamley]

Harley,

Pentax makes a lens cleaning fluid with an anti fogging agent. It works quite well. I live in the near the Smokies where morning humidity is often at 100%, so I've given it a pretty rigorous test. It does leave a film which is very slightly visible, but nothing I'd think would affect image quality in the slightest - and you can clean it off with regular lens cleaner.

http://www.bhphotovideo.com/bnh/controller/home?O=productlist&A=details&Q=&sku=249131&is=REG

Steve

[paul owen]

If your camera has interchangeable bellows then unlocking them from the front standard and allowing them and the lens to "breathe" is a good idea. You could also try removing the lens and compressing the bellows then extending them again! Good luck!

[Ken Lee]

When the equipment is cold, and the weather is warmer and damp, then it's not only the lens (front and back surfaces), but the inside and outside of the groundglass which can get fogged over, along with everything thing else, like your reading glasses, loupe, lightmeter, etc. Also your film and film holders. Oh joy.

If you warm them up by sleeping with them in your sleeping bag, or carrying them close to you, inside a coat or jacket, you're more likely to avoid the problem.

[CP Goerz]

Possibly keep the lens inside your jacket for a few mins prior to shooting to bring it up a bit in temperature so its closer to the ambient temperature. Another option is to give it a good spritz with some WD40 :-)

CP Goerz

[Paul Schilliger]

A common problem with early morning shots! Especially after a cold night spent in the outdoors. I have missed some nice shots too. If there is no way of shading the camera from direct sunlight, try putting a jacket or clear cloth over the bellows to prevent the sun from warming it, until everything reaches the ambient temperature.