Snapshot from the metro in Lisbon. This was not a carefully planned shot, but that's not how I get my best street shots. I focused on the far wall, waited for the train to arrive and hoped for the best. I think this photo does a decent job of displaying a hectic urban scene without a specific subject. The woman positioned between the train carts is pure luck, of course.
Shot with a Canon EOS 350D. I used my trusty (and cheap!) Canon F/1.8 50 mm for this shot, as I do most of the time in poor lighting. I used aperture priority because I don't normally have time to tune for manual when street shooting. Normally I would have used ISO-800 in this light, but since I wanted a bit longer exposure to capture the movement of the train I went for ISO-400. This resulted in a 1/50 exposure.
Editing: Channel mixer (for converting to black and white), curves (for contrast), resize.
Train stations are magical places to take pictures.