There are a few problems there that need to be taken into consideration.
Han had A FEW cameras watching critical parts of the ship. And it was only a freighter sized ship.
Despite the cameras a whole GROUP of people managed to sneak aboard without Han detecting them.
Then for Starkiller Base you have 2 areas.
The planet itself. Extensive landscapes with forests etc. Thus no way to surveil it all.
The base itself. Despite taking up only a small portion of the planet it still had a tremendous size way bigger than a typical industrial complex in modern days.
So what does that mean in conclusion? In modern days we have cameras at critical junctions, and other critical areas and still time and again suspicious people are overlooked. And as Han's freighter showed, cameras in Star Wars work similar to cameras in modern days, with one exception. Robots. They are shown to be quite good at finding people as shown in The Phantom Menace.
If we now think of Starkiller Base. It is far too large to have every area covered by cameras. Thus (if at all, because of the small portion we saw of the base we can't really tell) cameras would be put at only critical locations. And still there is a good chance that some important info is overlooked due to the vastness of the area covered and thus also the number of cameras involved.
So this means in essence. We can't tell for sure if there were any cameras there or not. As we don't see the whole area but only parts of it AND the info where Rey went and where the Wookiee was could have easily been overlooked by people manning the monitor stations.
The main question is though why they don't use patrolling camera droids. And from what we see of the First Order, they share the same "dislike" seemingly for droids as the Empire did. So that also wouldn't be done.