Photo Technic

Equipment care during winter
1) Battery
Most photographic equipment such as camera, flash, moterdrive, exposure meter, need batteries.
It is known that lithium batteries perform best at cold during winter time.

When it is cold, a newly charged set of batteries should be used. At extreme cold, you can preserve the batteries inside of your pocket to extend the power.
Prepare a reserve set of batteries.
2) Moter drive
It is not recommendable using a motor drive at slow shutter operaation.
At low temperatures, using auto-focus can consume a lot more power than normal because lubricants inside of a lens is frozen.
3) Storing equipment
You should pay more attention to lenses than cameras because lenses have many moving parts and the materials used for lens, glass, aluminum, plastics, and etc., have quite different thermal expansion coefficients.
LCD displays can get damaged at extreme cold.
4) Caring equipment after shooting
Before moving from cold outside to warm indoor, equipment should be put in a bag to prevent surface condensation.
Condensation inside of a lens can be critical.
If condensation occurs, it should be dcried as soon as possible using a fan.
But, lens shouldn't be wiped.
Equipment should be kept inside of bag until temperature is warmed not to cause condensation.
It will be safe to wait at least 30 minutes of so.
Heat shouldn't be used to dry condensation because peeling can happen to lens.
5) External battery pack
External battery pack should be cared without exposing it in a cold for extended time.
6) Tripod and ballhead
Wrapping at least one leg with protective sleeve can prevent freezing and coldness during cold weather.

A very thin film of lubricant (WD-40 for Markins ballheads) before going out to cold outside can prevent freezing and condensation.
When you setup a tripod on snow, it should be pressed too much. or, the legs can be damaged.
7) Storing equipment after shooting
If it is too dry, the water content inside of lubricant can evaporate. 40-50% of humidity will be better.