The sling pack is sufficient for a Nikon 3200 with wide- and telephoto lens. The Tele I put this in the top compartment. Also the charging unit and div. Kleinzubehöhr fit with inside or even a bite to eat. Drinking fits in the outer pocket. The handling is perfect, as you can very well take out at the part when it moves forward, everything or fill it. In addition, the ideal companion for mountaineering - is to wear a backpack no problem if one side or half bears the Slingpack forward - and even in ideal cycling (slipping in a flexed driving position is not forward!). Just something I've been looking for. Also very affordable price - that part is the "tight is right" market but smooth expensive by half.
