Edgar Stoel wrote:wich camera is the best to use.
Sorry, no pun intended, but the question in itself is wrong. There is no such thing as a single one best camera. You first need to decide what you want to do, then look for the right tool to achieve your goal. The blackmagic cameras are very different, but who's to say if you need the portability of the pocket cam? The added resolution of the cinema camera? The global shutter of the 4k production camera? No one knows the budget you are willing to spend. Or the lenses you already have. If you want to rig the system? Et. Cetera.
If you don't know which blackmagic camera is right for you, chances are that none of them are. They are called "cinema camera" for a reason, and this implies that you need a decent amount of hardware and knowledge to get the stunning visuals you might have seen in demo videos around the web, and especially in this forum.