Just as a painter must familiarize themselves with different types of paints or strokes of a brush so too must the photographer learn all they can about how a camera manipulates light.
While it’s true that cameras have never been more ubiquitous or easy to use, with options that automate most of its functions, it is also the case that skilled photographers—those who can operate cameras with knowledge and precision—are just as needed as they ever were.
To this end, it is important to learn all the functions of your camera, and how they work together to create, what is known in camera parlance as: reciprocity.
The three main functions of the camera the photographer uses to manipulate and capture light are: 1. ISO. 2. Aperture. 3. Shutter speed.
ISO stands for International Standard Organization. It is called this because every camera is required to read light the same way. The ISO controls the cameras sensitivity to light.
When learning about camera functions it can be useful to use metaphors to help you understand the concepts. For example, for thinking about ISO, it can be useful to to imagine it as a bucket of light and ask yourself: How much light do I want to put in my bucket for this picture?
A different metaphor for ISO would be to imagine your camera as a beehive, and your ISO is the number of bees. The only thing different about these bees is that they gather light instead of pollen. The darker it is outside, the more bees you’ll need to gather light.
Is it light with some shade outside? You’ll need 400 bees (set your camera to ISO 400). Are you in a room where the only light is coming from windows? Maybe it’s better to use more bees (set your camera to ISO 800). Of course, if it is really dark, like if you were trying to capture action at a evening sports event, you might need a lot of bees (setting your camera to ISO 3200).
Essentially, different ISOs are needed for different lighting situations. The ISO should always be the first thing you set on your camera.
Next is the Aperture. The aperture controls how much light you are letting in the camera, by controlling the F-stop: the diameter of the opening. The aperture functions to both control light and control the depth of field.
Going back to the camera as the beehive metaphor, the aperture is the tunnel the bees must crawl through to get out and gather light. If you open the tunnel up wide, your bees can get out faster and gather light quicker but don’t go as far. If you tighten the tunnel, it takes the bees longer, but they go farther.
Remember, the higher the f-stop (like f22) the narrower the aperture and the greater the depth of field, and lower the f-stop (f2.8), the wider the aperture and the shallower the depth of field.
Last but not least is the shutter speed. The shutter speed controls how long you let the light in. The higher the shutter speed the faster the action happens. Shutter speed functions to control light and control motion.
There are three main types of motion: blur, stop action, and pan.
In the beehive metaphor, the shutter speed is the door at the end of the tunnel that lets the bees in and out. The higher the shutter speed, the faster the door opens and closes.
Shutter speed is measured in fractions of a second. So 60, is actually 1/60, and 2000 would actually be 1/2000.
These three mechanics are the main things one needs to understand when operating a camera. Of course, there are many other elements to good photography, like composition, subject, etc. But knowing how to use the ISO, the aperture, and shutter speed in conjunction with one another to control light through reciprocity, is where any fledgling photographer must begin.