(Portland, OR) -- Police in Portland's Central Precinct will start wearing body cameras today. Portland is the last city of its size in the U.S. to require officers to wear body cameras. The high-definition Axon cameras will be used during most police encounters. Officers will usually tell the person they're being recorded and they can request to camera to be turned off. The cameras have a 30-second buffer before the officer starts recording. North Precinct will get cameras in July and East Precinct officers start wearing them in August.