[Chris Saper]

I've been painting portraits now for 15 years, and only used existing light for the first 11 years. It was really great for the work I was doing then.

Spontaneous work from life in sunlight has a unique quality ( Linda Brandon, the Egelis, John Michael Carter and Dan Gerhartz are worth your research)

How you approach this is entirely personal. I have (now?recently?currently?) come to the conclusion that using photo references taken outside are poor source reference photos, even with great cameras and Photoshop.

I am working hard to try to gain skill working with artificial light that mimics natrual light. I am definitely in the student mode, but I think that artificial light with the subject against the proper value background, gives me better modeling information.I can later drop in the background info.

I think you should consider how you want to paint in your future. Either go for the vibrant spontaneity of the outside work, or something else. I think it all depend on how you see your relationships with your clients and their needs and how you see your own work being played out. I don't mean to sound as if it's an "either or". There's so much room for many painters, and many approaches.