Well, there are camera-specific packs such as the Lowepro Pro Trekker AW II ($477), which can swallow two SLRs and a half-dozen lenses up to a long telephoto, plus all the accessories you might reasonably need. But it isnt really a backpacking pack, so it doesnt do a good job of handling all your camping gear. In fact, it does a lousy job.
But people have long carried camera gear when backpacking. I know I used to, before I got tired of adding 20 pounds to a heavy pack. The solution is simply to give each piece of camera gear its own protection. That means, for instance, buying a pair of holster-type camera cases such as Lowepros Topload Zoom AW ($70), which can swallow a big SLR body and a longish zoom lens. Or, go for an updated, front-facing fanny-pack of sorts with the Lowepro Inverse 100 AW ($80). The advantage here is that your SLR body plus an additional lens will be super easy to access.
Then, simply buy cases for individual lenses. Case Logic makes a series of lens cases from $15 to $25 that can handle most any lens.
It also helps to get a backpack with external pockets that are camera- and lens-friendly. Gregorys Baltoro 70 ($270) is pretty good on this countits a 4,300-cubic-inch pack with a large external pocket. Ospreys Argon 85 ($369) is a little larger at 5,100 cubic inches, and it has a large outside pocket as well.
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