Depth Of Field,F-stops & Apertures

What is Depth of field?

The zone of sharpness and extends in front of and behind the point that you have actually focused on. Depth of Field is controlled by three main factors, aperture, focal length of the lens and camera to subject distance.

As you can see by this image at f/1.8 it blurs out the background and foreground but focuses on the middle. Whilst at f/4.5 there is a little bit of blur in the very background and in the foreground but there is a deep depth of field in the middle. Whilst at f/22 everything in the shot is in perfect focus and a huge deep depth of field.

F-stops

Aperture & f-stops are terms for the same thing, the adjustable opening on the camera lens . They are measured in numerical values called f-stops. The most common found on most cameras are:- f2.8, f4, f5.6, f8, f11, f16, f22.

Apertures

The aperture stop of a photographic lens can be adjusted to control the amount of light reaching the film or image sensor. In combination with variation of shutter speed, the aperture size will regulate the film's or image sensor's degree of exposure to light.

Here is an example of aperture at 1/90 of a second on each shot. As you can see when you increase the aperture it gets darker as the amount of light allowed into the lens is alot smaller.