Just about any lens is a portrait lens… it all has to do with the distance to the sub-
ject and its granted real estate ratio in the composed frame at SR.
— A wider angle is ok to set a full figure subject in a space. < 40 mm.
— A "normal" focal length will do fine for a tighter frame half figure. 40 to 70 mm.
— Longer lenses are great for tightest frames. > 85 mm.
These focal length are expressed in FX terms.
Have a good time!
Technically, at the beginning to base one's learning process, go by the rules.Good advice. You should always learn how to do it correctly first but then it can be interesting to break the rules.
i have AF NIKKOR 35-70 MM 1:3.3-4.5 and NIKON DX AF-S NIKKOR 18-135 1:3.5-5.6G ED