Shutter speed

shutter speed

In photography and digital photography the shutter speed is the unit of measurement which determines how long shutter remains open as the picture is taken. The slower the shutter speed, the longer the exposure time. The shutter speed and aperture together control the total amount of light reaching the sensor. Shutter speeds are expressed in seconds or fractions of a second. For example 2, 1, 1/2, 1/4, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, 1/1000, 1/2000, 1/4000, 1/8000. Each speed increment halves the amount of light. 
Long-exposure photography involves using long-duration shutter speed to capture objects normally while blurring or smearing any moving objects. An example would be a city street in which the buildings remain normal in the picture, but the fast-moving cars whir by in streaks of color.