Portraiture is an interesting art and in recent years, I have felt more and more passionate about it. I do not believe a portrait is defined by placing individuals in front of the same backdrop or lights and simply documenting their features. A portrait should record a vivid sense of presence as well as appearance. Sometimes this means expanding the frame of view to include more of the background to show who and where you are. The effect is cinematic and with the right lighting, the result is breathtaking. I prefer not use backdrops, props or anything unnatural to add to a portrait unless necessary for its context and presentation. For instance, one exception to this rule is for sports/dance portraits where the print is part of a collage.
Environmental or Natural Portraiture can be candid or posed in a natural familiar setting that tells something about the subject. Portrait with your favorite instrument if you are a musician, at the workplace, or just doing what you do. For children, portraits are best at a local park. backyard, favorite spot to play or even in their own bedroom surrounded by their favorite toys. I have learned from myself and my kids that if they are doing something they enjoy, the smiles will be natural.