When you are taking photographs there is so much to consider. Have I got the composition right and included a point of interest? Have I chosen all the correct settings for the type of shot? And after all this has been determined, you still have to make sure your final photograph is going to be in focus. This photography basics article is going to look at focusing, with an overview of the choices you have in order to obtain the correct focus for the type of shot you are taking.

In most cases your camera will focus when you press the shutter halfway. This is what is called Auto Focus (AF). AF is perfectly acceptable when you are photographing subjects that do not move around (such as a portrait, or even a landscape). Depending on your camera this may be called One Shot AF or Single Shot AF.

When your subjects are mobile, there is another type of AF you can use, Continuous Auto Focus (CAF). In this mode your camera will be constantly focusing on the subject, which is ideal for moving targets, such as speeding cars or athletes. There are a couple of downsides, such as the batteries are under constant strain from all the focusing and refocusing. Remember to take spares in this case. There is also the chance of some noise in your pictures caused by the constantly adjusting focus, as well as a small increase in general wear and tear on the camera's mechanism.

Knowing what focus type to choose is one thing, but how does the camera know that you want to focus on Aunt Bessie, and not the trees that are behind her? To understand this we need to understand the photography basics that determine the focal point (or focus area) the camera is choosing.

In truth, your camera does not know (or even care) what your subject is. Why would it - it's a machine after all! But your camera is designed to set up a focus point, or areas, within the frame of the shot. Standard AF selects a relatively wide area around the centre of the frame for its focus. You will usually see this as a rectangle or brackets in your viewfinder or LCD screen. If your camera has Centre Focus (CF), the area of focus is reduced to a square. CF could be used, for example, when isolating one person from a crowd of people.

Finally, some cameras go another step and include a feature known as Multipoint Focus (MF). In this case, the camera can select from a number of areas within the frame, so that the photographer does not always have to have the centre point as the area in focus. A number of modern compact cameras use a variation of this to produce Face Detection, in order that the photograph will be focused on peoples' faces. This function is particularly useful at social gatherings where the photographer wants to easily, and quickly, take shots of friends and family.

I hope this article has helped you to understand some of the photography basics regarding the way your camera interprets focus points, and the auto focus options available to you.