Some people are great at taking photos of their con sketches; I'm not one of them. I usually end up never seeing the sketches again, however, at times, I get scans sent to me or end up finishing the work outside of the con hours and can get a scan made before I give it to the fan (like the Green Lantern/Sinestro sketch I posted over the weekend).
I met Marc Wolfe at the Toronto Fan Expo last year. He's a helluva great guy and a damn fine artist -- as you can see here. He started a sketchbook for his very young son, Ronin, and I got to be among the first to contribute to it!