Maybe a better approach is to stick your cameras on their own vlan, then deny access to WAN and LANS. From your other LAN allow access to the WAN and vlans.
Use an alias in the rule to define your networks .50, x, etc.
You might need an exception to access the wifi depending on how you have set it up.
If you just want to leave the camera on IOT then yes you need a rule to allow LAN 192.168.x.0/24 to talk to 192.168.50.0/24. If you move the cameras to their own network, same answer that an allow rule from 192.168.x.0/24 is needed to access that camera network.