Most of you already know what is exposure. But some of my visitors are just beginners and they are not familiar with photography terms. So i decided to write about basic photography once in a while. Today’s topic is exposure as you can see above.

Exposure is amount of incoming light to the camera during a single shot. If the sensor or film exposed to light too long, the picture will be washed out or over-brightened in other terms. If film or sensor exposed to light to short, then the photograph will be too dark. Modern cameras have light meters that shows you ideal exposure settings by measuring the amount of light in the scene. But sometimes it is better to set the camera manually.

Two main factors that affect the exposure level of the picture are; shutter speed and aperture. Shutter speed, determines how long the sensor or film will be exposed to light and shutter speed is measured in seconds or fractions of a second. 2′ means 2 seconds and 1/60 means one sixtieth of a second which means 16.6 milliseconds. And aperture is the size of the gap in the lens that lets the light into your camera. Aperture is measured in f/stops, as the number with the f increases the gap in the lens gets smaller, and as the number decreases gap gets bigger and lets more light into the camera. f/2.8 is a wide aperture and f/22 is a narrow aperture.

Both of aperture and shutter speed are used to control the amount of light that enters into the camera but with different effects of photograph. As i wrote in my earlier posts, shutter speed is the control that freezes the movement or gives the feeling of speed by making the subject or background blurry. On the other hand aperture controls depth-of-field* determining what is in the focus. A wide aperture like f/2.8, can be used to isolate one object by blurring the objects in front and back also background. A narrow or small aperture like f/20 makes everything sharp in the picture, which is good for landscape and architectural photography.

There’s one factor that affects the exposure, which is ISO, sensitivity of film or sensor to the light. Higher ISO value means higher sensitivity to light, which allows you to take pictures without a tripod when there is not enough light, but as everything, high ISO comes with a cost, which is grain or noise in digital photography. Grain or noise reduces the quality of image by adding small visible particles which is not good for large prints. I advice you to set the ISO to low values if you have enough light. ISO 100 is the lowest ISO in most of D-SLR cameras, and 1600 - 3200 are the highest.

*Depth of Field : is the part of the scene that appears sharp in the picture.