Photography Basics Chapter 1
ISO, Aperture and Shutter Speed (The Exposure Triangle)
The Photography Basics series makes up the essentials any aspiring photographer should get comfortable with in order to capture that composition you are looking for. Our first instalment will be dealing head on with the Exposure Triangle, closely followed by chapter 2: Lighting and Gear. Each time you press the shutter release button, there are a number of actions that take place inside your camera, resulting in an image. None of this would be possible if there was no light. Today we are going to cover the exposure triangle. It is a very important concept when it comes to handling manual and semi-manual mode.
The Exposure Triangle
The three elements that make up this trifecta are ISO, aperture, and shutter speed.
ISO
Is mainly concerned with the sensitivity the sensor has towards light, the higher the ISO value we choose, the more sensitive our camera sensor is the more light it will capture.
Aperture
It is the size of the diaphragm, that is, the chamber that is inside the lens, and that allows light to enter. The larger the aperture, the more light will enter and be recorded by the camera’s sensor.
Shutter speed
This is the time during which the camera is held open by recording the light or picture. Usually they are fractions of a second, which last a shot, but can be more extensive. In fact, at slower shutter speeds, more light enters the camera.
The combination of these 3 variables to a lesser or greater degree will affect the photography. More importantly, every change in any of these 3 factors will impact the other 2, which means that in manual mode you can not change one of these 3 without taking into account the other 2.
Understanding the Exposure Triangle
Capturing a moment actually literally implies capturing the light that is reflected from our subject. With this in our minds, imagine yourself in a room with a closed window. There is no light source other than the natural light that enters through the window that is initially closed. In addition imagine wearing sunglasses. If we wanted to light that room we would open that window, but if we wanted to have make the room much brighter, we could enlarge that window. It is true that a larger window would give us more light. In photography that window is called aperture.
Now imagine that we cant enlarge the window, but we still want to make it brighter. We could start by opening the window, but the longer we left it open, the more light would enter, with the slight difference that in the room light dissipates and therefore does not build up whereas the camera’s light sensor does. As this is the closest reference to shutter speed. If a DSLR camera in “m“ (manual) mode is set with a 2 seconds shutter speed, the light will be doubled if the initial speed was only 1 second.
Remember that you’ve been wearing sunglasses since we started the example. These sunglasses symbolize the ISO value which when set at a low setting will only allow just the right amount of light in. What if, with the window open, you take off your sunglasses? Your eyes would simply receive more light. The same happens when we raise the ISO to high values, with a small difference that affects DSLR cameras, at higher levels of ISO noise/grains can start to appear).
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Mastering the Exposure Triangle
By mastering each one of these 3 variables separately you will learn to control them as a whole. If you want a little trick for those who are taking their first steps in manual mode: use the semimanual modes of your camera and learn from observation. Modern camera’s come with various “priority” modes, in Aperture Priority mode (“A” mode in Nikon, “Av” in Canon) what you control isthe size of the aperture. Try to change that value and see how the camera automatically changes the other factor like the shutter speed. If you put a small aperture, f / 16 for example, the camera will choose a slower shutter speed, if you choose a huge aperture, type f / 2.8, you’ll see that the shutter speed will be faster.
Side effects
Each of the 3 factors described above has side effects, sometimes its exactly what you are looking for. Aperture has a direct impact on depth of field, ISO influences the amount of grains / noise that will appear in the photo, and the shooting speed influences how we capture action or movement).
These photography basics provide you with the tools to start taking professional grade photography. You should be able to challenge the light in your photographs and tame it to get the captures you want.
