In my upcoming related video on JAKphoto, I explain how every single camera works, ever, in under 5 minutes. And it’s very likely this is how every camera will continue to work in the future. With these fundamentals in mind, you can operate any stills camera providing these settings are adjustable. Of course, there are many other things to learn in photography. Perhaps the next-step is the Sunny-16 rule, but that will require a basic knowledge of what we’re about to cover. So.
This is the easy one. We’ll likely all have a grasp of what focus will do. It will shift different parts in an image into sharper detail or out into blur depending on the distance that those subjects are from the lens. That’s it. Got it!? Great! Let’s move on.
ISO in photography means how sensitive your medium is to light. “Medium” being what you are capturing the image on. This could be a digital sensor, film, glass plate covered in silver halide, etc. Everything has a certain sensitivity and the more sensitive, the brighter the image, the less, the darker. The unanimous trade off, regardless of medium, is noise. You increase the sensitivity, you get more noise. OK. NEXT!
Sometimes referred to simply as time or exposure time, the shutter speed is how long you open up the camera and allow light to hit the medium. The longer the light hits it, the brighter the image is, the shorter, the darker. (Seeing a trend here?) The trade off is that exposing for long periods will record any kind of movement as motion blur, - whether you’ve moved or your subject has moved.. Speed things up and you get things sharper, Of course, that can be used creatively so really, this isn’t a downside but an artistic choice. That was easy, right!? On to the home straight!
Aperture is the opening of the lens than can be varied using blades like a futuristic spaceship airlock. So as you may have guessed, this is yet another point to let more or less light in and result in brighter or darker images. The thing about aperture is that the wider you have it, the less focus you have in front and behind your subject (if you’ve put your focus on your subject!) and the tighter you have it the more will appear in focus. So, with landscapes often being entirely in focus (deep depth of field), they use a small aperture compared to that “blurry background” portrait that has used a large aperture to achieve a shallow depth of field.
And that’s it! That’s how every single camera works, ever! From a huge old bellow camera that's loaded manually, one slide at a time all the way to the phone in your pocket. Some of these points may not actually be adjustable on a given camera. For instance, many phone cameras have a fixed aperture (no blades!) or using film will mean your sensitivity is stuck for the amount of images on the roll but still - all other settings, options, filters or effects that cameras might give you are surplus to creating the initial image. Thankfully, all of the numbers that relate to each of these settings are universal. They're measurements or dimensions, time or set by the International Standards Organisation (yeah! ISO!). So, now you know!