Cold weather protection

[SWI]

Looking for some insight regarding protecting my lens and camera during a upcoming cold weather shhot in Montana next March.  I've watch the videos and already know about the power supply concern.  My concern is that would it so cold out as to effect the lens from functioning?  I'll be shooting with a 500 as well as 100 to 400 and a few smaller primes.  I just returned from Monument Valley where it appeared the 500 stopped working after several hours in the cold of night (no focus no IS).  Is there a "sock" or other outter garmet other than raingear?  Or am I worried about nothing and just be prepared to work around the cold.  I really don't see me standing out in the cold winter of Montana for the same period I was in Moument Valley were it only got down to the mid 30's.  Yes, I am expecting much colder weather in Monument Valley.  Any help all is welcome.

[matt4626]

I was in Yellowstone last winter 0 - 15 degrees some days. No problems with 500 f4 or anything else. Only thing I was careful about was bringing the stuff into a warm room - condensation was more of a problem that the cold.

[francois]

..Only thing I was careful about was bringing the stuff into a warm room - condensation was more of a problem that the cold...
[a href=\"index.php?act=findpost&pid=52429\"][{POST_SNAPBACK}][/a]

That's where the problems start! Bringing cold equipment even in a heated car will fog the lens. Other than that, I've never experienced any issue in the cold except for the rear LCD.