EXPOSURE, APERTURE & ISO

Your choice of aperture will give you control of how much of your shot is in focus. A wide aperture, which confusingly has the smallest ‘f-stop’ number, will enable a fast shutter speed, reducing motion blur. This gives a really small depth of focus. Ideal for portraits. Let’s say for example, on a certain day:

If you would like more in focus move the aperture to f4. You will be halving the area of the lens’s aperture. So as a result you have to double the amount of time the shutter is open. Simple! So the below combinations will give the same exposure but differing depths of focus:

Whilst you will be successfully increasing the depth of focus, conversely your shutter speed is getting slower and slower and that can effect motion blur. So be careful here and if you are using a long lens stick to a fairly open aperture.

ISO

You can also adjust the camera’s sensitivity to light, known as ISO. An ISO of 100 is slow, giving you rich, detailed colours, but requiring a longer exposure. An ISO of 800 or above (some cameras now go up to ISO 6,400 or more) is fast, but will result in a grainier image with flatter colours.

The higher the ISO, the grainier and flatter the image, but it will help avoid blur in low-light conditions

Increasing your depth of focus using the aperture can cause motion blur