Maybe I'm a luddite, but my system works on Mt. Hood, in the Wallowas, in the Andes, and the Himalayas. I use a holster with loops on the back for a waist belt - Tamrac is my fave due to the opening design which combines a single, secure clasp on a lid that flips back and a full zipper for security and weatherproofness. Adjust the shoulder strap so the holster rides at the level of the pack wiast belt, then thread the waist belt through and head on up the trail. Works with fanny packs, day packs, climbing packs, and big multi-day backpacks. Camera is readily available via the clasp, back in when done (handy when the weather is nasty). I've used this system without any issues since 2005.