When you take a picture with a camera it is called an exposure. How an exposure looks depends on 3 settings on your camera. Aperture, Shutter Speed and the ISO. We will discuss each of these and what impact they can have on your photo.
Aperture is the size of hole in your lens that allows light into the camera. It is also commonly referred to as an F-stop since the Aperture is the letter F followed by a number. Just to be confusing, the smaller the number, the larger the hole, so F1.4 is a very large opening while F22 is a small opening. In general, the smaller the F-stop number (and therefore the larger the hole) the more light can enter the camera in a given time.
Shutter Speed is how long the hole (Aperture) is left open to collect light. This is usually listed as a fraction of a second or number of seconds. This can vary from a very fast shutter speed like 1/8000 of a second to leaving the shutter open for minutes at a time. The faster the shutter speed, the better you can capture or stop action. The slower the shutter speed, the more light you can collect, especially useful in low-light conditions or to capture the blur of motion.
ISO (International Standards Organization) is the acronym developed during the days of film camera where film was categorized by how “fast” it was which really means how sensitive it is to light. A “faster” film collected more light than a “slower” film. Film speeds generally varied from ISO 100 to ISO 800. Today with digital cameras the same ISO numbers apply, but you (or the camera) can choose them and change them between shots, unlike the film days where you had to use an entire roll before you could switch to another ISO. In general, you would use a lower ISO when you have plenty of light (or in some cases you are shooting a longer exposure) while higher ISO is better for low light conditions. One downside of a high ISO is that you can end up with a grainy look depending on your camera’s ability in low light.
So when you take a picture on Automatic, the camera decides what Aperture, Shutter Speed and ISO to use. If you switch your camera to Aperture Priority (A, not to be confused with AUTO), you can select the Aperture yourself and the camera will decide on the best of the other two. Same thing for Shutter priority (S or Tv on Canon) , you pick the shutter speed and the camera decides on the best for the other two. If you switch your camera to Manual (M on most cameras) you are in complete control of all three! SCARY!!
These are the basics of the Exposure Triangle, we will dive into more detail on each in later posts.
Below is an info-graphic which captures the pieces of the Exposure Triangle we have discussed below. The first block shows you what the Exposure window on your camera looks like, you adjust one or more of the three exposure elements to position the marker at zero take a balanced picture. The second graphic shows what the Aperture looks like at different settings. The third graphic shows the Shutter Speed and gives an idea how that works. The last graphic shows the ISO and how ISO sensitivity affects your exposure.
I’ve also included a link to my Pinterest page of Photography info-graphics. It is a wealth of helpful Photography Tips and Tricks. Check it out!
This entry was posted in Photography by Rich