I'm looking for a sling-type bag to hold my camera + two lenses, maybe some extra batteries. I have a Tenba Messenger Bag with camera insert for traveling, holds my MacBook Pro, camera, lenses, speedlite, batteries, etc. Looking for something to be able to wear while shooting, with easy access for changing lenses quickly. Primarily for shooting concerts, so I can hold onto my equipment while shooting. I have a Nikon D80 Gripped, 50mm, 28mm, and 18-135. I would probably only carry the 50 and 28, plus extra batteries and memory cards. Any suggestions?