Aperture: The part of the camera that opens to let light in. The f-stop or f-number is the measurement of how open or closed the aperture is.
Depth of field: The difference between the closest and furthest in-focus objects in a photo. A shallow depth of field means that relatively close background objects become blurry. A deep depth of field means that faraway background objects are still in focus.
Dynamic range: The difference between the darkest and lightest tones in an image — the range of dark and light that a camera is capable of. Darkest and lightest hues are very rarely pure black or pure white. Cameras usually have a lower dynamic range than the human eye.
The combination of aperture, ISO and shutter speed, which determines the time and intensity of light being let into the camera. Different exposures in film and digital images alike are achieved by adjusting these exposure settings.
Focal length: The distance (usually measured in millimetres) between the optical centre of a camera lens and the camera sensor (sometimes called the image sensor).
The size of the aperture opening, also known as the f-number. A small f-number means the aperture is open more. A larger f-number means it’s open less. For example, f/1 lets in much more light than f/6.
ISO: How sensitive your camera is to light. A higher ISO will be more sensitive and photos will generally be brighter. A lower ISO less so. This term used to apply to film, but in the digital era it is now a camera setting. ISO gets its name from the International Organisation for Standardisation, a group based in Switzerland that began standards for industrial and commercial products, including cameras, following World War II.
Shutter speed: How long the camera’s shutter is open and the sensors inside are exposed to light. Very high shutter speeds are used for things like capturing a moving subject without blur. Low shutter speeds, for example, are often used for nighttime photography or by landscape photographers, which benefit from more light entering the camera during the longer shutter duration.