Alisa, what zoom have you just got? The 80-200 zoom on my Canon digital equates to a 128-320mm zoom on a normal 35mm format. As I try to shoot these sort of pics wide open to minimise DOF and maximise shutter speed at a setting of 100 ISO, a monopod is almost essential to minimise camera shake at still relatively low shutter speeds. If you haven't already got one, think about a monopod - extremely useful for all type of work where carrying a full blown tripod around all the time is impractical, etc. FYI this was shot at f2.8, 1/60 sec. at a 35mm equivalent of 200mm.
really good portrait there Street Man...wish there was a bit more info in the back but none the less it works very well as a portrait anyway...crop the very bottom up to the soles of his shoes...that step is a distraction