L.A.: One frame at a time

On a steep slope, above a retaining wall with scrawled warnings (“Stay off, Stay out, Private Property”), William Ahmanson left, helps friend and business partner Colin Rich set up to shoot downtown Los Angeles.  (Christina House / For The Times)

Onlookers enjoy the sunset as Colin Rich shoots a time-lapse sequence. When he identified a good vantage point, Rich would scout the area during the day. A time-lapse photographer has to deal with a host of variables and complications: light, vehicle traffic, curious pedestrians, shifting weather conditions.  (Christina House / For The Times)

Colin Rich checks his camera while shooting on the Sixth Street bridge in downtown Los Angeles. Technical challenges abound: choosing the right shutter speed, exposure levels or combination of filters. Sometimes, small mistakes reveal themselves only when Rich reviews images on his computer afterward. The only solution is to go back out and try again.  (Christina House / For The Times)

Colin Rich’s camera catches downtown Los Angeles at sunset. Security restrictions imposed after 9/11 make it difficult to photograph near downtown buildings and Los Angeles International Airport.  (Christina House / For The Times)