Sign up only for Antarctica trips. Seriously, DEET is probably the best of the insect repellants, but it doesn't really work great for photographers. Why? Because if you get any of it on plastic parts of your camera, especially in concentrated form (more on that in a bit), it tends to soften the plastic and lead to some real ugliness. I once saw someone (not me) leave a perfect fingerprint in the top plate of his camera. Nice trick if he needed to ID the camera after a theft, I suppose, but nevertheless a constantly visible reminder of the dangers of DEET around plastics.
So, here's Thom's quick and dirty insect avoidance advice:
- Look for repellant products with Picaridin (e.g. some Repel options). Generally works as well as most DEET, lasts long (up to 10 hours), and is safe around plastics and camera gear. Some people believe that Eucalyptus and Citronella Oil work, but I’ve not found them to be as effective nor as long-lasting as Picaridin.
- Invest in clothes treated with permethrin. They come in names like Insect Shield, Bug Off, etc., but you can make your own by just buying a bottle of the stuff at your local outdoor retailer. And those should be long-sleeved shirts, full pants, socks, and a hat at a minimum. You want to be fully covered, and you want your coverage to repel insects.
- If you're headed into really nasty bug country, a head net is really useful. And consider some really thin gloves treated in permethrin.
- You're still going to have exposed skin (mostly your neck and head). You can protect your neck with a permethrin-treated buff, or by just keeping collars up and tight. On any remaining exposed skin use a picaridin-based bug spray, if possible. You'll probably have to apply it more often, as my experience says it doesn't last as long at repelling at 33% DEET.
If you have to use DEET, a few things to keep in mind:
- You don't need 100% DEET. Military testing showed that 25-33% concentrations do just fine and higher concentrations really don't add to repellence (they might lengthen the time the DEET works, though). The lower the concentration, the less likely you'll experience the dreaded plastic warp.
- Consider using swipes instead of a spray. The pre-moistened towelette versions allow you to make sure you're only applying it to areas you want to and not to everything via a not-so-well-directed spray. Make sure you wash your hands thoroughly after applying DEET this way. You absolutely do not want DEET on your fingers, palm, and inside wrist, which come in contact with your camera equipment all the time. Likewise, consider not putting any on parts of your face that come into contact with the camera all the time.
- Carry a small towel or wiping cloth. Keep perspiration from dripping onto your equipment and wipe off the equipment itself if you suspect you've gotten DEET directly on it. Wash the towel frequently.
- Keep the DEET itself inside a plastic Ziplock bag. The worst damage I've seen happen with DEET occurred when the repellant leaked in someone's pack and spread directly over equipment.