Imagine your world in black and white…
This system is split into 10 sections:
0 – Being pure black
5 – Being mid grey
10 – Being pure white light
A photograph will consist of a variety of zones, ranging from pure blacks to pure whites. Some great examples of the variety of zones you can include in one photograph can be seen in Ansel Adams and Edward Westons work. But an image I have been greatly inspired by in the past, to create a wide range of tones in my own photography, is by Bill Brandt, whose image is displayed bellow.
To get a mid grey exposure (zone 5) of your subject then you can use a light meter, which we were shown how to use this week in a workshop. A light meter will only ever give you one reading, which is zone 5, so depending on where you take the reading within your image, that section will be mid grey. If you were to photograph a subject in front of a bright background and took the light meter reading from your subjects position then the background will become over exposed. Take the reading from the background and the subject will be under exposed and will appear as a silhouette. Here are some examples of photographing with a light meter.
As you can see from these first two images (left, centre) the mid grey area is where the light source is coming from, as that is where I took the light meter reading from. Because the rest of the image is darker than the area I took the reading from, it is under exposed. The light meter reading of the third image (right) has been taken from the centre of the room but the light coming through the window is a lot brighter. This has caused the light in the background to look over exposed.