There are many photographic possibilities when temperatures drop below zero degrees Celcius and if you adopt a few simple practices your shooting experience will be prolonged and will preserve your cameras for future outings.
Battery performance is decreased in sub-zero temperatures but it’s important to know that they are not necessarily draining more quickly. Despite what your camera may suggest a battery indicating a low charge can often be resuscitated simply by warming it up. I recommend having at least two batteries per camera body with the spares being carried close to your body where it will remain warm. Make a switch whenever the cold battery is indicating a low charge and each time you’ll discover that the once "depleted" battery inside your clothing will now indicate a greater charge. Continue this routine throughout the day and you’ll get much more life out of your batteries.
Not all batteries are created equal so shop carefully. I prefer to stay away from third-party manufacturer’s batteries because sometimes they do not hold a charge as well and may not “communicate” with your camera to provide you will the battery level. This is the case some after-market batteries made for the EOS 1D Mk IV, which is why I now make the investment and purchase only the Canon batteries.
Chemical hand warmers are a great addition to your kit that will not only keep your hands and feet warm in a pinch but can be used to keep your batteries warm, even while shooting. As part of a larger series on the Arctic I shot a three-hour time-lapse above the arctic circle - during a very short day - and needed to leave the camera in the elements to do its thing. To help preserve my battery’s function I left the 5D MkIII body I covered it with a waterproof cover and taped a hand warmer to the body adjacent to the battery compartment. It worked like a charm!
When shooting extreme long exposures or time-lapses in the cold the possibility of your lens fogging up is very real. A simple solution is to wrap a hand warmer or two around the body of your lens. A bit of tape or elastic bands can be used for the temporary fix.
Condensation on and inside your equipment can be another danger which may limit the lifespan of your equipment. If you are moving your gear inside at all condensation will form when the warm air comes into contact with the cold air surrounding the camera. Everything will fog up, possibly including the elements inside your lenses. Should you then go back out into the cold you will have a major problem with ice on, and possibly inside your camera. The way to avoid this is to seal your gear inside an airtight bag before going inside. The condensation will form on the exterior of the bag and not on your gear. Carry a few ziplock bags in a variety of sizes that will fit your equipment and keep them where they can be easily accessed. These bags now come large enough to fit a full camera bag in if need-be.
Remember that snow is solid and will not leak inside or melt on your equipment. Even if your camera is buried in powder you can simply brush it off, give your lens a wipe, and get back to making photographs. Just don’t use something warm on your lens, or blow on it because that is when you will leave fog or water residue behind.
Next week I’ll share my system for staying warm while shooting in winter.