how can I avoid this? Tried my first star trail shot the other week, and was forced to stop after a few exposures because of lens fog. I heard hand warmers around the lens, but there's got to be a better solution than this?
Nikon makes a product.. Nikon - Fog Eliminator Cloths (3-Pack) - 8073 - B&H Photo Video It ought to work on Canon too.
Also try using your lens hood. It will help reduce the fogging by shielding the element from direct exposure to the night sky. Although the more vertical you get the less this will help obviously.
Acclimate your gear. If you plan on using it on a cool, damp evening, or a hot humid day, sit it outside in that environment for a couple of hours in advance.
