Awards, Grants, and Contests

Humoyun Mehridinov

Award: Top 100

School: tis
Teacher: ahmad itani
Category: Contrived
Photo #19543

Memory of Light

Just like the retina in our eyes,  any camera's sensor accumulates light particles,  or photons. Once the shutter,  which acts as a curtain,  opens for a hundredths or even thousandths of a second,  the light penetrates the sensor consisting of millions of photosites,  or pixels. When photons hit the pixel - the microscopic light-sensitive area of silicon - they knock off a loose electron,  as a result of which an electrical charge is generated. This is called the photoelectric effect. The amount of electric charge depends on the intensity of light,  and determines the color and brightness of that individual spot on the photograph. Such a short time of a hundredth of a second is usually enough for light to pass through the lens and get recorded to the sensor during daytime; however,  interesting patterns emerge if the shutter is left open for a longer period of time in low light conditions.

In long exposure photography,  the exact same technique is used. The camera is set to leave the shutter open for periods ranging from several full minutes to hours - in this photo,  it's 30 seconds! As the shutter is open,  the reflected light from moving objects in a way "carries on" across the whole sensor and sensor records that trail,  thereby creating the motion effect. As opposed to moving objects,  objects that are stationary,  like that white car,  do not produce such an effect because they reflect light only in one direction of the sensor for the whole 30 seconds.