I'll be trekking in the Nepal Himalaya for 3 weeks in December, in a variety of conditions, but predominantly cold (-5°C to -30°c) , clear and dry, at altitudes of up to 6000m.
I'm trying to travel light so would prefer to take the minimum of paraphernalia; if I can stick to a single lens, that would be ideal. I predominantly shoot landscapes, but I'm hoping to do some wildlife and portraits whilst I'm out there too. Which lens would you take?
In terms of budget, I'm not overly converned, although if I can keep it under $1500 (£1000) that would be nice.
edit: thanks for the answers so far, I've been reading through them all and checking out the specs, but I keep finding myself drawn toward a 24-105mm f/4L (possibly with a nice and light 50mm f/1.4 for low light), or possibly a 24-70mm f/2.8L. Any thoughts on these options?