Backpacks are superior for carrying heavy gear for long distances, but access has always been a problem. Also, traditional front-loading backpacks get wet and dirty when placed on the ground.
The BackLight 26L, with a rear-panel compartment for photo gear, allows you to access your gear without taking off the backpack. You can change lenses or just snap a quick photo by simply by spinning the bag to the front of your body while the waist belt is still secured. Rear-panel access also adds security when traveling since your camera gear is protected behind your back.