Exposure (Exposure)

Exposure means the film or sensor absorption into the amount of light, it consists of the diameter of the lens opening (aperture) and the film or sensor photosensitive time (shutter speed), and the efficiency of the exposure is determined by the film or sensor sensitivity. Based on these principles, we can launch the exposure value (EV) from the aperture, shutter speed and ISO speed. We define exposure means the film 0EV or sensor absorption into the amount of light, it consists of the diameter of the lens opening (aperture) and the film or sensor photosensitive time (shutter speed), and the efficiency of the exposure is determined by the film or sensor sensitivity.

Based on these principles, we can launch the exposure value (EV) from the aperture, shutter speed and ISO speed.

We have to define as the aperture 0EV f/1, 1s shutter speed, ISO speed (ISO) to 100 of exposure. Whenever the amount of light sensor absorption by half (for example Aperture or shutter down level adjustment twice as fast), the exposure value will increase 1 EV. For example, absorption of sensors in 6EV into light, the amount of half the. 5EV EV value is used for high bright environment, in these environments, the film or sensor just absorb very little light, the photos will have slain.

The following examples we spoke.

If your shutter speed to 1/125s, Aperture to f/8, speed parameters for ISO 100 film, the exposure value is 13 EV. When you tune into the shutter speed 1/250s (exposure time by half) and the aperture larger level i.e. f/5.6, the exposure value EV still equal to 13. Or do you tune into the shutter speed 1/250s, keeping the aperture size is unchanged, but will speed tune into ISO200, this also will draw EV = 13. However, increasing the speed will increase digital camera imaging noise and film camera imaging of particles.

In AE mode, the camera according to the exposure of the need to combine control the aperture, shutter and ISO value, but this feature is implemented through the metering system.

A high value implied shooting EV bright environment, you need a small high shutter speed, Aperture and/or low speed, otherwise photos too resigned. When you use Aperture priority mode, the camera will follow a fixed EV value Select shutter speed; in shutter priority mode, the camera will follow a fixed EV value Select aperture value.