"The tourist is taking few pictures."
Translation:Keveset fényképez a turista.
That is one of the several ways a verb is created from a noun. It will usually mean "doing the normal, regular activity with the given object". There is probably no specific rule, you just have to learn them one by one. But you will see many verbs that are a derivative of a noun this way.
This is a VERY odd construction and something that will not be useful in any other context, according to my native Hungarian speaking wife. WHY, one might ask, are they wasting our effort on it???