Understanding exposure is one of those fundamentals of photography that we all need to master, but as a beginner…well it can be a doozy.
Before we get into the resources for understanding exposure below, let me give you a very basic overview.
Exposure refers simply to the amount of light that reaches the film or sensor in your camera.
There are three settings that impact exposure – or how bright or dark your images are – and these functions together make up the Exposure Triangle.
ISO, ShutterSpeed, and Aperture all interact with each other and how you select the settings for each give you the effect you want for your image.
ISO – refers to how sensitive the film is to light (in DSLR cameras, this refers to the sensor setting instead). If you are taking photos on a bright, sunny day, you'll want to use a low ISO setting (probably ISO 100 or 200). If your scene is poorly lit, you'll probably use a high ISO; Warning…higher ISO settings will show up unwanted graininess, called noise, in your image.
Shutter Speed – this is the amount of time the shutter on your camera is open. If you only have the shutter open for a short time, less light hits the film or sensor and you capture an image snap frozen in time! The longer the shutter speed, the more light hits the sensor or film and any movement in the frame will show as blurred.
Aperture – this is the size of the opening in the lens that lets light through to your film or sensor. The wider the opening the more light is let in and vice-versa. The opening is measured in “f stops”. The smaller the “f” number, the larger the opening – as you increase the f-stop, the size of the opening decreases, with less light entering your camera. Aperture allows you to control depth of field.
So that was a very quick overview of exposure and the exposure triangle, but here are 7 essential resources that will help you understand exposure.