If the camera mounting is counterbalanced you should not need much torque to move it in either direction.
If servos give you sufficient control they will be very much simpler to install, to power and to program than a stepper motor. I suggest you build a rough system and try it with servos before concluding that stepper motors are needed.
Note, however that normal servos only move through about 180 degrees. If you need a full 360 deg movement you will probably need a sail-winch servo or, perhaps, gearing to convert 180 deg into 360 deg. The HobbyKing website has a huge selection of servos if you want to study what is available.
...R
Stepper Motor Basics