I was shooting with a Canon EOS1D MkII and a Canon 24-70 f2.8L lens. I wasn't able to move myself around too much without shifting furniture and would have preferred to be shooting nearer the telephoto end of the range to deliberately remove any clutter. As it was, the lens was at 34mm (add the 1.3x factor and you get a 44.2 full frame equivalent field of view) and I cropped the image to the "letterbox" shape.
In this case I used the subject himself to mask the flash which was a Canon 550ex speedlight triggered in manual mode by a Canon ST-E2 transmitter. The first few frames had the background (a wall in my dining room) pretty evenly lit, which was a bit boring. The background is unimportant in this image and so the depth of field doesn't matter too much. The exposure was 1/90th of a second at f13 on 200 ISO. I don't recall why the exposure was 1/90th instead of 1/250th to utterly eliminate any available light but in a normal situation I would have gone for 1/250th.
I have some grid attachments for my Lumedyne flash heads and so I taped one of those over the flash to give me more of a circular pool of light. I aimed the flash slightly upwards so that I achieved the effect that you see above. It's a very simple image that works for the intended purpose very well.
The second example is from a story I shot for a magazine about two brothers who work together at a school in London. I had shot hundreds of images of the buildings and a lot of portraits of the elder brother who is the boss. I had a lot of more conventional portraits of the two of them together as well so I decided to try this two person silhouette which shows the special cladding used throughout the central core of the building.