Can fit Nikon D750 + 1.7x Nikon Lens Extender + 70-200 VR Lens (just barely, but works!!) in side access pocket.Divider system is well padded and/with solid velcro adhesion.Vented straps (all of them) are excellent.Back padding is equally well ventilated.Waist straps relieve shoulders of most weight - works VERY well.Adjustability of shoulder straps is excellent.Easily carries aforementioned camera (above) with 2 other lenses & a Canon 6D w/ 70-300 attached.Outer pocket can be used with a small Osprey 1.5L Hydraulics Reservoir... but bag overall will be heavy with that.Haven't tested water resistance yet but I imagine it's fine & this bag includes a rain cover.For reference, I'm ~ 6' @ 150lbs, 32 waist.