Image Format

The most common image formats are 4:3 and 16:9.

4:3 format is what all domestic TVs were for many years past.

16:9 is what we have come to know as widescreen (as used in modern LCD & plasma TVs and computer monitors).

The first figure refers to the image width.

The second figure refers to the image height.

Plainly these values are expressed as a ratio, meaning that (in the case of a 4:3 monitor) if you measure the monitor width and divide it by four, then it's height will be three times that resulting value. It is a fixed ratio; the scene height will always be this proportion of the scene width.

You always need to bear this in mind when considering any particular scene to be monitored with a camera. The format ratio is fixed i.e. if you decide to view a wide scene, you will by default also capture a tall scene - it is impossible not to!

Wide scenes = tall scenes = small people in the scene = a lack of people detail.

We'll talk more about this in our explanation of 'Field of View' (FOV).


The format that you actually use is determined by the image chip in the camera, it cannot be adjusted or changed.

Ideally, you would aim to view the images on a monitor with a matching format, and therefore endeavour to ensure that all cameras on a system are the same format.