Understanding your camera is key to getting great photos for your site. Want to get those professional, multi-dimensional photos like the pros, but only have a standard DSLR camera? It's all about the aperture, baby.
1. The aperture is the size of the opening in the lens when a picture is taken. When you hit a button to take a picture, a hole opens to allow the camera to capture the scene — the aperture you set affects the size of that hole. The larger the hold, the more light goes in, the smaller the hole, the less light.
2. Aperture is measured in f-stops (you will see it referred to as f/number, like f/2.8, f/4, f/22, etc.).
3. Moving from one f-stop to the next doubles or halves the size of the amount of opening in your lens. Simply put, it doubles or halves the amount of light coming into your camera.
4. The one tricky thing you MUST remember — large apertures (where more light is let in) have SMALLER f-stops, and small apertures (less light) have LARGER f-stops. In context: f/2.8 lets in much more light than f/22.
5. The depth of field (DOF) is the distance between the nearest and farthest objects in a scene that appear acceptably sharp in an image.
6. Large depth of field means that most or all of your image (meaning both foreground and the background) is in focus, or sharp. For this effect, you want a larger f-stop, meaning a smaller aperture or less light getting in.
For example, most of the background is in focus, giving it a large DOF and a small aperture:
7. Shallow depth of field means that only a part of the image is in focus, and the rest will be blurry or fuzzy. For this effect, you want a smaller f-stop, meaning a larger aperture or more light.
For example, the background is blurry, leaving only the subject in focus, which is a shallow DOF and a larger aperture:
8. One way to keep all this straight in your head: small f-stop numbers mean small DOF, and large f-stop numbers mean large DOF.
9. When you think about the type of photo you want to take, quantify whether you want a large or shallow depth of field and adjust your aperture accordingly. In most cases, landscape photography will have small aperture settings because they want a large depth of field. However portrait photography generally is shot with a focus on the subject and a blurry background (shallow depth of field), with a large aperture.
The best way to learn? Pick up your camera and practice! Soon it will be like second nature.