avoid using direct lighting planes for lighting.
in real life studio shooting, lights are shot into white canvas which will create an area light with soft scattering effect, so a better way of doing studio lighting is to set area lights that shots AWAY from the object, and rely on the reflected light from the wall to lit the scene, the result is much smoother and more natural.
lighting planes are only good when you need a solid highlight area, which is not suitble in all scenes.