Recommend a good desiccant.
Sometimes I move from a cold air conditioned environment to a warm humid outdoor one. After a while there can be fog buildup inside the lens.
Is there a good brand/type of desiccant which you guys can recommend?
I plan to put a whole bunch in a pelican case and place the lens in it to let the moisture dissipate out.
Here's what I do. I go to the pharmacy and ask them to save the desiccant cannisters that come in their larger jars of drugs. They transfer the drugs to smaller bottles as they dispense prescriptions and then throw away the silica gel. After a week, they've saved enough of them to fill coffee can for me.
I prefer the solid cannisters with silica over the little bags. I don't want to introduce dust into my camera bag.
I'm a woodworker and thus have several hundred high grade steel cutting tools. So I pop silica capsules into every drawer of every toolbox. Then, every few months, I gather them up, toast them in a 150° oven for an hour to expel moisture and recharge the silica. The plastic on the capsules will melt, so keep the temperature low enough to avoid that, but high enough to drive out the moisture.
Living in the midwestern US the summers can get fairly humid. I store my gear in a padded shoulder bag with a desiccant container made by Pelican that's reusable and is about the size of a deck of cards....... http://www.bhphotovideo.com/c/product/242571-REG/Pelican_1500_500_000_Silica_Gel.html
Living in hot and humid Thailand I keep all my photo gear possible in a Pelican case with four of these desiccant packs. 10-15 minutes in a microwave oven at a very low power is enough to dry them out for resuse.
Living and loving it in Bangkok, Thailand. Canon 7D - See the gear list for the rest.