The Speed Box M is well thought out, offers quick access in (via "sling") on the DSLR. You can alternatively open the entire main compartment, there then is convenient access to the camera and has space for 2-4 additional lenses. With me fits well an EOS + angesetzem Tamron 17-50 2.8 (and sun visor), a Tamron 10-24 3.5-4.5 and a Canon 55-200 4.5-5.6 in. The subdivision can be changed flexibly, so I also could accommodate the rest of the sun visor.
The upper compartment provides plenty of space for more things that you need on a tour, and there is a front front compartment for memory cards, batteries, etc. and even a rain cover was intended. As a "coronation" there is even a front Stativhalter - if that makes sense in a sling backpack, everyone must decide for themselves.
It always raises only the question of whether the Sling concept is always the best option. For one thing, the objective change is difficult when you do not want to settle the backpack - there is a risk that the lenses fall out (here there are alternative systems such as Lowepro Flipside). Furthermore, does the "slingen" only good if you closed clothes wear (eg no open jacket, otherwise you always pulls the jacket). In addition, one has only one strap, which is inconvenient on long trips. But this may Xtrem + nothing, that's just the concept.
Conclusion: If Slingbag, but then the Speed Box M!
