Holster/strap to use with full backpack

I do a lot of long-distance trekking in the mountains with a full backpack, usually anywhere from 35 to 65 litres. There's quite a bit of scrambling involved, so I can't use a traditional strap to carry my DSLR. I've done quite a bit of searching, but I haven't been able to find a harness that I can use to keep my camera stable and close to my body but relatively easy to access to take pictures on the fly. There's a harness out there that attaches to light, book-bag type backpacks, but nothing that would attach to the larger shoulder straps of a full backpack. There are also a couple of harnesses out there that you can wear under the backpack. These are what I've used, but they tend to let the camera bounce. Any suggestions? via /r/photography https://ift.tt/2EvLOud