Dan I have the Lowepro Pro Runner 300AW and have found it to be comfortable in use. I load the following in the bag Canon 50d, 100mm f2.8 macro, 17 - 85mm EFS, 70 - 200mm f2.8 L, 400mm f5.6L, all the cables , remote control cable, spare CF cards, manuals and the camera is not attached to a lens...