What they used for Obama's official portrait.

This here is Obama's official presidential portrait, taken with a 5D Mk II. If you zoom up close, you'll notice you can see so much detail! Especially on his face.

Well, they used a macro on him. 105mm Canon. Just goes on to show how powerful a macro lens can be when used as a portrait lens.

[Word of advice: DON'T use a macro lens for a portrait of anyone even remotely self-conscious.]

The photo is also brilliant lit. That's not the work of the 5D Mk II, though. If you zoom in on the eye and enlarge it, you can see what really were used to make the pic so brilliantly effective.

There's a umbrella on the left. With a strobe attached to it, definitely. That gives the main source of the light. And on the right a large reflector's been used. This adds some nice light on the other side of the face, so that there are no harsh shadows present.

There. Simple and efficient! And you've got yourself a great portrait, something that could even be used by the President of the United States!