# Definition: Algorithm (Computing & photography)

#### Algorithm

An algorithm describes a set procedure to complete a task in computing. It comprises the actions needed to complete a specific task, or for solving a specific problem.

The term algorithm, is normally applied to computer applications. Packed into the modern camera are all sorts of computer components. Each ‘function’ on your menu calls up a computer program. So, the on-board computer runs the program to complete the task. We use the word ‘algorithm’ to describe the procedure each of those programs follow as they run.

##### Algorithm examples

An example algorithm might be the control of the auto-focus process in your camera. Another example might be the calculation of shutter opening duration for a correct exposure.

An algorithm can also describe the cumulative effect of many algorithms.  Sub-tasks are often considered important individually. Together, as a number of steps, they complete a larger scale task.

##### An algorithm produces your *.jpg files

When you push the shutter button, you activate a series of processes in your camera. Modern digital cameras have a range of algorithms. Each algorithm contributes to complete the overall process. The photographic process might look something like the steps below…

1. Frame the picture in the viewfinder;
2. The lens will Auto-focus on the subject;
3. Internally, the camera will raise the reflex mirror;
4. The camera will open the shutter for a calculated period.
5. An Automatic exposure is completed by the camera;
6. Data is collected from each photo-site on the digital image sensor;
7. Data is changed by the camera according to the menu preferences;
8. The camera will create the *.jpg file;
9. The file is stored on the memory card.

You are now ready to take the next shot.

Each of these steps in the taking of a picture is a separate algorithm. There are many others too. Together they control your camera to create the image files that make your picture.

The list above forms an algorithm that describes the overall photographic process. Each simpler step is an algorithm too, as they each complete a task in their own way.

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Damon Guy (Netkonnexion)

Damon is a writer-photographer and the editor of this site. He has run a major website, a computing department and a digital image library. Damon started out as a trained teacher and now runs training for digital photographers.
By Damon Guy see his profile on Google+.

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