Yes but it really need to be separate if the networks were connected together on the lan side of the routers both would send out DHCP and you would have problems.
It depend why you want it seperate. If it is to protect the cameras from people on the internet the easiest method is to either leave the gateway blank in the ip configuration or set it to some unused ip address. Since the camera does not know how to get out of the network it will only talk to local machine.
Most IP cameras do not send a lot of traffic. Many have limitations of 8-16mbits so it would take a lot of cameras to cause issues on a gigabit based lan network.