Tamrac Expedition 8x - it carries my Chamonix 5x4, 4 lenses, 10 double film holders, meter, filters, etc, etc. Velcro partitions can adjust to your needs. Tripod straps on in the middle of the back and sits in a foot pocket. It's well padded for protection of equipment. And there's plenty of room for a DSLR and lunch and drinks. Its also very comfortable - well, as comfortable as anything can be when the whole load weighs in at 35 to 40 lbs. Unladen it's not going to be the lightest of what's on offer but it's an excellent choice. I've used mine for 5 years and it's got several years left in it yet.
Check out F-Stop Gear - http://fstopgear.com/. They make a line of bags including 3 technical backpacks. You store your camera/lenses in ICUs (internal bag) which can be swapped out of the backpacks (when in the bag they're held in place by velcro straps attached to the backpack frame). They have four different sizes of ICUs so you can mix/match. The whole thing is comfy for long hikes, and it doesn't look like a camera bag.
I'm using the Tilopa right now (medium sized bag) with a large ICU. I'm going to grab and extra large ICU so I can carry two more lenses. Right now I'm carrying a Toyo 45cf, Fujinon 125mm f/5.6, Fujinon 250mm F/6.3, 10 holders, a Sekonic light meter, loupe, release cable, filters and a notebook in the main ICU compartment. Darkcloth and changing bag are in the main compartment, with plenty of room for a jacket, lunch, a digital SLR and other odds and ends. You can't see it in the pics but the backpack flap also has two see-through pockets to store stuff. There's also an external top pocket and a large rear pocket, as well as a roomy internal laptop sleeve. If for some reason this isn't big enough, they make a larger bag called the Satori.
I just got a F-Stop Satori EXP with Large Pro ICU at the weekend. They are expensive but are very good. Currently have my Ebony 45SU and all the accesories in the ICU and 3 additional lenses in a seperate Photobackpacker lens case. Still sorting out the best arrangement but the comfort already makes my gear feel slightly lighter.
These are exp0ensive, but there is a good reason they are continually short on stock for the past 2 years.
And actually the best part of these bags is the zipper on the back panel. That way the back panel never sits on the ground getting dirty or muddy anf then, in turn, getting your shirt messy.
I recently got an extra large pro ICU for my Tilopa that I'm very happy with.
In the ICU alone -
- Toyo 45a
- 90, 150, 250, 400T
- 7 holders
- light meter
- color meter
- lee filter holder and 5 filters
While the Photo Backpacker stuff looks nice, I'd hate to have to zip/unzip every case for every shot.
My 5x7 Speeder lives in a Jansport Equinox. No complaints.
I steal time at 1/125th of a second, so I don't consider my photography to be Fine Art as much as it is petty larceny.
One thing which never comes up is the color of the pack. I hate loud stuff outdoors, though bright gear can obviously be easier to spot if you wander away from the camp.
I like Forest green or blue. There's a reason for it. Bugs like the showy color. But the worst
of all is black fabric. It gets hot and mosquitos think you're a bear. Unfotunately, I got a
real good deal on a huge black pack which I need to use this summer. The solution - a hiking partner with a light complexion - not a mosquito repellant, but an attractant!