Think Tank TurnStyle 20 Convertible Sling Bag
The Think Tank TurnStyle 20 is a sleek and practical sling bag designed to hold a standard DSLR camera, along with several lenses and plenty of other accessories. There are tons of little pockets throughout the bag for pens and memory cards and whatnot, along with a larger pocket on the back side that can comfortably hold a full-sized iPad. Watch this video review to get a better idea of how much the bag can hold.
When it's time to go shooting, the TurnStyle 20 converts to a beltpack so you can easily get your gear in and out of the bag. Either way you wear it, the bag is quite comfortable even for long shoots. It'll run you $100 on Amazon.