Since I'm now trying a completely rackless bikepacking setup, I need to be able to put some light and bulky item on the back, but an ordinary backpack unsurprisingly turned out to be suboptimal for this. Some googling and a few questions on the Finnish cyclist forum fillarifoorumi quickly led to me buying a (slightly) used LowePro Photo Sport 200 AW, which promised to be very suitable for my use. It has a large enough padded camera compartment accessible from the side without taking it off completely as well as a 13.9 liter upper compartment. All the reviews say that it is very light, but at 1.3 kg it doesn't really seem so from an lightpacker's point of view. Anyway, here are my first impressions of it:
Loaded with some camera gear and clothes in the upper compartment it sits well on the back. At home I confirmed that my winter sleeping bag would fit there, though it was a tight fit. The waist belt is rather light and flimsy, but since I won't load it with more than 3-4 kg it won't be a problem for me.
No problem getting a Panasonic GH2 with the Olympus 14-150 mm lens mounted to fit. A few extra lenses and a flash unit also fit without problems. In fact, there is a little too much room (m43 gear is small), but the tightening system does a good job of preventing things from bouncing around. There is no good place for memory cards, though.
The backpack seems to be what I was looking for. I will use it for bikepacking trips, but probably not for ordinary rides, since the Lowepro Slingshot 102 AW works well for that and I have room in my frame bags for some extra gear. There is also a smaller slingshot version of the backpack, the Lowepro Photo Sport Sling 100 AW, which could be a good option if less room is needed.