Just getting caught up posting a few headshots from weeks recent (and not so recent).
These were made at two different sessions and I made my gear changeover between them. The first two--Betsy and Steve--were shot with the Nikon D700 and a Tamron 90mm f/2.8 macro lens (which makes a fine portrait lens) back in February. Mark's, the third one, was made with the Panasonic GH3 and Lumix 35-100mm f/2.8 lens just this week.
The lighting setups were slightly different for each session as well. For the February folks, I used a Nikon SB-800 speedlight in a 28" Westcott Apollo softbox. You can see the square catchlight in the eyes. Shadows are filled in opposite the main light with a white reflector, and I lit the white seamless paper background with a single SB-800 as well.
For Mark's session, I used an older Nikon SB-26 speedlight into a Westcott 43" double-fold reflective umbrella as the main light. Why not the Apollo? Why not. I like to mix things up and see what works. I did, however, use a white reflector for fill and a second SB-26 on the background. This is a simple headshot lighting setup that always gives me consistent results.
I almost always deliver headshots in square crops or horizontal rectangles to my clients. I've never really liked the look of vertical headshot portraits. But since a vertical portrait is what nearly everyone sees when they see a headshot, my clients' images stand out because they're different.