Smaller volume day hiking backpacks (1,800 cubic inches to 2,000 cubic inches) will generally hold a good amount of gear, plus a small amount of clothing or accessories. Larger volume packs (2,000 to 2,500 cubic inches) will hold even more.
This is a serious backpack designed for demanding photographers and videographers. With its technical styling, the Whistler looks more like a hiking backpack than one aimed at photography, but don't let the looks fool you -- it's well-designed for photographers. The 450-denier ripstop nylon exterior has TUP face coating, Nifco side-release buckles, Duraflex hoops and a Hypalon base, and comes in gray with eye-catching orange accents. The pack also includes an All Weather cover -- hence the AW in the name -- which can be easily stowed away when not in use.
For the reasons mentioned above, I believe good day hiking backpacks should have a good waist belt and padded back. The belt doesn't need to be large. It will add only ounces to the pack but gives you the option to carry additional gear (i.e., overnight gear) much more comfortably. That's just my opinion. Other people think a waistbelt gets in the way or want to cut every ounce possible. At the least, day hiking backpacks over 2000 cu in should have a waistbelt. And if large enough, an internal frame or some sort of support system.