Camera Exposure

A photograph’s exposure determines how light or dark an image will appear when it’s been captured by your camera.

UNDERSTANDING EXPOSURE

the exposure settings of aperture, shutter speed and ISO speed are analogous to the width, time and quantity discussed above. Furthermore, just as the rate of rainfall was beyond your control above, so too is natural light for a photographer.

EXPOSURE TRIANGLE: APERTURE, ISO & SHUTTER SPEED

Aperture: controls the area over which light can enter your camera Shutter speed: controls the duration of the exposure ISO speed: controls the sensitivity of your camera’s sensor to a given amount of light

Shutter Speed

A camera’s shutter determines when the camera sensor will be open or closed to incoming light from the camera lens. The shutter speed specifically refers to how long this light is permitted to enter the camera. “Shutter speed” and “exposure time” refer to the same concept, where a faster shutter speed means a shorter exposure time.

Aperture Settings

A camera’s aperture setting controls the area over which light can pass through your camera lens. It is specified in terms of an f-stop value, which can at times be counterintuitive, because the area of the opening increases as the f-stop decreases.

Iso Speed

The ISO speed determines how sensitive the camera is to incoming light. Similar to shutter speed, it also correlates 1:1 with how much the exposure increases or decreases. However, unlike aperture and shutter speed, a lower ISO speed is almost always desirable, since higher ISO speeds dramatically increase image noise.

Camera Exposure Modes

Most digital cameras have one of the following standardized exposure modes: Auto (green rectangle), Program (P), Aperture Priority (Av), Shutter Priority (Tv), Manual (M) and Bulb (B) mode. Av, Tv, and M are often called “creative modes” or “auto exposure (AE) modes.”