Hi,
We use Mikrotik and have about 50 devices.
We have allso about 10 Wireless camera's.
These camera's are 802.11B, 802.11G and 2 of them are 802.11N

Is it better to create a new VLAN for this IP camera's only so our users are not disturbed in there Wireless signal and speed?

If your concern is the 802.11B clients slowing down the Wifi speed of 802.1N clients that is going to occur at the Radio not at the router. Meaning no changes to the router can help you.

If you want to throttle the Wifi clients so Cameras have more speed them you can do this with a queue.