Day Four of the desert canyon hike, and that's the recurring thought that runs through your head so you indulge yourself by taking a deep sip from the hydration pack that lives in the camera bag. In the camera bag! On your back. Now that's cool.
All this while you're tirelessly snapping photos of your hiking club partners, charging across the landscape. It was good thinking on your part to house your gear in the Lowepro Flipside Sport 15L AW. Aside from protecting your pro-sized DSLR with attached grip and long-zoom lens in almost any weather, it holds additional tools, like extra lenses or some flash units. It has attachment points for carrying a tripod or a monopod, and even a spot for a hiking pole, not to mention a zippered pouch for personal items and small accessories.
All this in a daypack form factor that's ingeniously designed to swivel about your hips when you shed the shoulder straps, providing easy access so you'll be ready for that critical shot in seconds. No taking off the pack to slow your mobility. Take another sip. You're gonna need it.