I am planning to climb Mt. Shasta this May. I've carried my D800 up Mt Whitney and a few other mountains, but those were trailed "hikes", not mountaineering. I also carried the D800 over 100 miles on foot through an African game park, so I am not shy about where I take the camera, but Shasta is snow, glaciers and ice with crampons and ice axes and I don't think a large camera on sling.or chest pack is going to be practical. I'm beginning to think a lighter and perhaps cheaper camera would be better. I would be interested in hearing about anyone's experience or suggestions with any of the smaller enthusiast cameras in such potentially harsh conditions. I tend to shoot primarily 20 and 28mm primes and a bit with my 85 if that helps.