Exposure is one of the fundamental terms in photography. When you press the shutter button during shooting to open the aperture, light enters and triggers the sensor. Exposure is the amount of light that hits the camera’s sensor, generating visual data over a period of time. This period of time can be fractions of a second or entire hours.
Proper exposure is a matter of finding balance
Overexposure results in “blown out” bright areas and washed-out images. Underexposed images are dark and indistinct. Learn the basics to understand what camera exposure is and how to achieve the right exposure for your shots.
The exposure triangle
There is no separate setting for selecting exposure on a camera. Instead, exposure depends on three different settings, known as the exposure triangle. These settings are: shutter speed, aperture, and ISO.
Shutter Speed
Shutter speed is the amount of time the camera’s shutter is open. It determines the length of the exposure. Shutter speed values on modern cameras are measured in fractions of a second. Standard shutter speeds for daylight photography range from 1/1000 to 1/200 of a second. The appropriate shutter speed depends on the lighting conditions.
If there isn’t much light, you will most likely need a long exposure. You can get a well-exposed and well-lit image in low light conditions if you adjust your camera settings correctly. When shooting at night, some photographers leave the shutter open for several seconds. When shooting with a long exposure, the photographer can sometimes leave the shutter open for several minutes or even hours. Keep in mind that the longer the shutter is open, the more motion blur there will be in the final photo. Tripods are a great tool for controlling motion blur.
A shorter exposure allows you to capture dynamic scenes. If you are photographing an event and want to capture people’s expressions, you need an exposure of 1/400 or higher. If you’re shooting something even more dynamic, such as a sporting event, you should use a very short shutter speed. For example, photographers who shoot the instantaneous movements of athletes may use a shutter speed of as little as 1/1000 of a second to capture the exact moment a basketball player shoots the ball into the basket.
Aperture
The aperture is an adjustable opening in the lens that controls the amount of light entering the camera. It acts like the pupil in the human eye, which dilates to let in more light and constricts in bright light. The aperture value is measured by what is known as the f-number, or aperture number. The smaller the f-number, the wider the aperture, and vice versa. f/8 corresponds to a smaller aperture, while f/2 corresponds to a wider aperture that lets in more light.
A food photographer might use a wide aperture to achieve a shallow depth of field, where the subject is in focus but the background is blurred. Imagine a piece of cake that looks sharp and clear, but the edge of the plate behind it is blurred. A large depth of field is used for landscape photography, where everything from the trees in the foreground to the mountains in the distance appears sharp, detailed, and in focus.