The exposure of an image determines how light or dark an image will appear. This is determined by three camera settings:
- Shutter Speed
These are also known as the exposure triangle. Each setting controls exposure differently. In a camera’s lens there’s a hole which allows light through, which allows what the camera sees. Therefore it allows what you can see. It’s the same with our eyes. Our pupils is the opening in the centre of the iris. Keep that in mind when you think about how a camera works.
Aperture (F stop) – controls the area of size which light can enter into the lens. (Controls how big the pupil of the iris is). The bigger the hole the more light comes in. If the F stop is too large then the image will come out over exposed.
Shutter Speed – controls the duration of the exposure. How long the camera takes to take a picture. “Shutter speed” and “exposure time” refer to the same concept, where a faster shutter speed means a shorter exposure time.
ISO Speed – controls the sensitivity of your camera’s sensor to a given amount of light.
A photographer can use many combinations of the above three settings to achieve the same exposure. The key however, is knowing which trade-offs to make, since each setting also influences other image properties. For example, aperture affects depth of field, shutter speed affects motion blur and ISO speed affects image noise.
Wide Aperture –
f/2.0 – low f-stop number. Shallow depth of field.
Narrow Aperture –
f/16 – high f-stop number. Large depth of field.
LONG EXPOSURE PHOTOGRAPHY:
When you use a tripod you eliminate the camera from shaking and distorting the image. It is integral when taking long exposure photo’s such as light painting but not so much for motion blur, although in some cases it is ideal to use a tripod.
Slow shutter speed / Light painting / Motion blur:
The paths of moving light sources become clearly visible. Long exposure can be used to capture the effect of time in an image.
SHORT EXPOSURE PHOTOGRAPHY:
Taking a picture with a short exposure time means using a fast shutter speed. This is ideal when trying to capture sports or just freezing motion. I.e. dropping a pebble into water. Short exposure captures an instant of time, something that happens in a fraction of a second.
Cinemagraphs are still photographs where a minor and repeated movement occurs. They are usually published as an animated GIF, and give the impression to the audience that they are watching a video. They are commonly produced by taking a series of photographs or a video recording. Then, using software, the photos are made into a loop of frames.
Here is an example of a GIF/Cinemagraph