Course is for a amateur photographer (me fall into this category according to all with "only" a body) more than enough available. I get in without problems:
Canon EOS 600D
and
EF-S 18-55mm kit lens (Standard lens), EF 50mm 1.8 II (compact Prime), Sigma 8-16mm F4.5-5.6 DC HSM (relatively large super wide angle), Tamron SP 70-300mm F4-5.6 VC USD (relatively large telephoto zoom)
plus
a Yongnuo YN-468 (external flash) with diffuser.
It would still be loosely fit in a large lens and even then would still for a little knick-knacks place (eg charger + cable). Currently, I can put the flash in the front pocket and got so inside room for a small bottle of water, etc. (0.5l), which I find very convenient also - more than the camera bag you do not want to carry around most.
In a side pocket I have 3 filters including storage packs, in the other batteries for the flash (here's loads of space). In the front pocket I have spare batteries for the cam, cleaning supplies, Objektivrück- and camera cover and a hot shoe; I can put everything into the side pocket, if I instead the flash vornerein pack (see above). Inside pocket in the lid, I have a few cables and a card reader USB stick. It even fits still a Nexus 7 tablet flat cross placed under the lid, which I super place also (is not the only way to travel very useful thanks to GPS and Wi-Fi, but also at the same remote control for the cam - in the 600D wired).
