beginners, skill level 1

How does a camera work & why should I care ?

You may be thinking ‘ I don’t need to understand how a car works to drive it’

True, but…..you do understand that a car engine runs on fuel and it drives four wheels that go round and round at varying speeds depending on how much you accelerate, you know what the brakes do and why you need them and you understand the effect of gravity.

Understanding what’s going on ‘under the hood’ of a camera really will help you understand what all the buttons and options do. And demystify the whole thing and put YOU in control.

A camera is simply a box of darkness, with a tiny hole that lets light in and focusses it onto a sensor which records the image. We need to make sure the right amount of light gets in, this is called ‘exposure’.

There are three main components that drive a camera, all of which work in tandem with each other and all of which can be adjusted to suit whatever we’re taking a photo of and what we want our photo to look like ;

Stay with me, understanding this will help you understand all the settings and buttons

1) The lens - where the light enters and the scene is focussed. Lenses differ in focal length, i.e. how wide or how zoomed in the scene is. For now we’ll just leave it at that.
What’s important is the aperture - a hole in the the lens, that can be made big or small or something in between. It’s a method of controlling how much light gets in. (It also controls how much of the scene is in focus, more of this later)

2) Next comes the shutter. This is a door that opens and closes, again letting light in. You can control how much light is let in by controlling how long the door is open for.
You need a fast shutter if you want to freeze movement, a long shutter if you want to blur movement or if you don’t have much light to work with.

So the first two are the ‘light controllers’. The next one is the ‘light receiver’ ;


3) The sensor - this is where digital and film cameras differ. Digital records the image onto an electronic sensor, film records it onto a plastic sheet coated with light sensitive chemicals.
The sensor can be made very sensitive to light or not very sensitive. It depends on what your aperture and shutter are doing and how much or how little light you have to work with. Making the sensor more sensitive has a negative effect on quality, this is when photos look grainy.

Forgetting the lens for now, it’s just glass, these are the three things we have control over - aperture, shutter speed, sensor sensitivity
They are all adjustable BUT they all work in tandem - so if you adjust one, it has a knock on effect on the other two. Don't worry about that for now, just know that it's the case.


In MANUAL the photographer decides, along with help from the light meter, what to set each one to.
In AUTO, the camera decides which settings to use for each. It bases it’s settings on an ‘average’, so if you’ve ever made exposure mistakes, it’s probably because the camera didn’t understand what you were trying to photograph. Maybe the photo came out too light or too dark or too blurry.

Inbetween Manual and Auto there’s AP (aperture priority ; you decide the aperture, the camera decides the shutter speed, and SP (speed priority ; you decide the speed and the camera decides the aperture)

Every camera has a light meter, so you may be thinking ‘but I don’t know what to set anything to !”. Have no fear, your camera will tell you if it needs more or less light, so it’s just a case of fiddling with the settings until the camera meter says ‘yes, I’ve got the right amount of light coming in, I’m good to go’.
We go into this further on our beginners courses.
Your camera may have different modes, like ‘landscape’, 'portrait' or 'sunset' mode for example. These are options that are very like Auto, but you’re giving the camera a bit more info about the scene so it can make the right decisions with the settings.

Let's think about what the camera will be assuming with these settings :
Landscape - you’ll want everything in focus and there’ll be a lot of light to work with because you’re outside. So the camera will set a shutter speed that’s fast enough for you to be able to hold without causing any blur, it doesn’t need a really fast shutter speed because unless it’s blowing a Force 10 gale, things aren’t really going to move enough to cause a problem. It will set the aperture so most of the scene is in focus.
Portrait - you’ll want just the person in focus and just the person to be exposed correctly, the background and foreground can go hang. The camera will give you a shutter speed that can freeze an expression, (It may also offer you a ‘burst’ of takes, to make sure you capture the right expression and no blinking) and an aperture that just focusses on the subject you've focussed on, the rest can go blurry.
Sunset - you’ll want the photo to be quite dark, so all the colours are rich. You’ll only need the horizon to be in focus. So the camera will base it's shutter speed and aperture on these requirements.

Once you start to understand what the camera is trying to do and what it has to work with, it will all start to slot into place. Then you get to a point where you can fiddle, you'll start to understand when you want a wide aperture, when you don't and with practice you'll be able to make those adjustments easily.

At the beginners workshops, we go into this in more detail and test it out.

If you have any questions, please get in touch