A long focal length throws the background out of focus.

Taken at the beached hulks at Purton on the east bank of the Severn - I've been here many times, usually in winter under leaden skies, but yesterday's visit saw the best weather for a long time. This fantastically photogenic and eerie place was deserted, leaving me to wander uninterrupted around the schooners, barges, trows, colliers and lighters, beached in an effort to shore up the eroding banks of the river. http://www.gloucesterdocks.me.uk/canal/graveyard.htm has more info and a bit of history.