Check out this video from Karl Taylor as he shoots photos of a model with window light, studio lighting, then adds makeup and then adds post-production in Photoshop. It provides a pretty powerful demonstration of what not only Photoshop can do, but also what quality studio lighting can do for portraits.
Karl Taylor Shows Powerful “Before & After” Photoshop and Lighting Demo
[youtube https://www.youtube.com/watch?v=318iFsOOWr8&w=700]