A good bag for the EOS M with standard lens. In the outside pockets can be good nor take spare batteries. Otherwise fit in not much, and the strap of the camera is something in the way. As you might have to plan some space for. The original flash of the camera I do not have, so I can only speculate. With attached flash but the camera is unlikely to fit into the pocket. If one takes him, he probably fits next to the lens. A larger flash definitely needs its own pocket.
