I often go into an environmental portrait shoot with a bunch of great ideas. Within the first 15 minutes or so you can often find them on the floor around where we are shooting. There's a tension between being prepared and ending up being too rigid in my approach. So I like to show up with a bunch of things that I have thought through, which I try to use as a guide as we shoot, but it's also important to just follow where things naturally lead.
When photographing one person though, I tend to start out thinking about how I can do so using one light. It's really important to consider available light too. One habit (not sure whether it is a bad or good one) that photographers who use flash have can be to simply assume that flash is always necessary. When shooting a particular kind of work, it is difficult to imagine shooting it with only available light. The real issue there is, if you are expected to get the shot and it needs to be of a certain style and technical quality, it's crazy to hope that available light will be your friend when you arrive at a location. On the other hand though, it is important not to discount the possibility of unbelievably good available light, and only that. I know, current digital cameras have unheard of high ISO functionality, and that is a great tool. But that table lamp is not always casting the best light on your subject, or that fluorescent fixture on the ceiling may not be the look that the commercial client is going after. So I bring lights.
Last week I photographed an excellent musician, Alex Prezzano, both in my studio and in a few locations around the building. He was great! Alex wanted me to create and had no interest in dictating a style to me. So we walked around the mill where my studio is located and did some setups. My goal was to have the shots look as natural as possible. The available light was not always what I needed, so I used one light. The little secret is that moving around a location like this with a speedlight on a stand makes things much less nuts too.
A lot of people are put off by any shadow on the wall. I love the look of one light with an simple reflecting umbrella. If there's a shadow, well, there's a shadow. Light makes shadows where it cannot fall. Rembrandt was partial to that look too, as I recall. No, I didn't know him personally...he lived in Europe.
After taking the photo walk around my building, we landed back in my studio. If a client wants a traditional look for a headshot, I use at least two lights and one or two reflectors. But here we were still going for a more dramatic look, so my default starting point is always that single light source. Here I did break out the 24x36 inch softbox, but used it at almost 90 degrees to camera right to give him a very dramatic effect.
Alex liked some work that I had done with a grid spot from the back hitting a gold reflector in front. This is a very cool effect because there is no light in front of the subject, and it is so soft and warm.
Adding a second light, finally, from the back as well, creates a really interesting effect too.
Check out Alex Prezzano's work here: http://www.myspace.com/alexanderprezzano