Diffused

Light is diffused when spread out, rather than directed in one spot. This softens the light and reduces contrast. Clouds are a natural diffuser, evening out light. Light from a studio flash can be diffused through a lightbox attached to the light itself. Attachments for camera flashes to soften the light can also be bought.

Depth of field

'Depth of field' is the term used to describe how much of the photograph is in sharp focus. This is often used for effect and to emphasise certain features of the photograph. 'Large depth of field' is when everything is in focus; 'small depth of field' is when most of the photograph is blurred, with one sharp area.

Aperture

Aperture is used to create depth of field and determines how much light you are letting into the camera. The aperture is traditionally in the lens of the camera. Reducing aperture is often called 'stopping down'. A small aperture (f22 for instance) creates a large depth of field, where everything will be sharp. A small aperture (f2 for instance) creates very little depth of field; only the subject that you focus on will be sharp.

Here is an exercise to help you understand how aperture works

Hold up your index finger and focus on the finger, then on the wall behind (use a wall which is not too close to you). Can you see both in focus at the same time? Take a piece of A4 paper and make a very small hole with the end of a biro. Now, look through the hole at your finger and at the wall. Can you see the finger and the wall? Are they both in focus now? The hole in the paper is a small aperture.

Shutter speed

Shutter speed also determines how much light you are letting into the camera, and is traditionally in the body of the camera. On mechanical cameras you can hear the shutter open and close. The shutter speed you select will determine the amount of movement or blur that you capture. If you have the shutter open for a long time you will see blurring as subjects move across your field of view (you will need a tripod for this). If you use a very fast shutter speed (like sports photographers) then you will freeze movement.

Try taking photographs of a fountain or a running tap with a tripod at different shutter speeds. Write down all your camera settings.

Contrast

A photograph with a lot of contrast has deep blacks and bright whites but few greys or midtones. Contrast gives a photograph drama but can also reduce detail. The higher the speed of your film the more contrast you get, as the grain in the film becomes bigger.

Colour casts

The camera does not see the same colour that our eyes do. Our eyes adjust to the varying light sources to recognise familiar colours. Different times of day, glass, and fluorescent lights all leave a colour cast that cannot be seen with the naked eye. Photographers use different types of filters and film to counteract these effects. Digital cameras correct these casts without the use of filters.

Saturated colour

Colour is saturated when intense or very bright. This happens at particular times of the day (early and late) and can be achieved through using particular film types, designed to give you strong colour. There is contrast in black and white and colour photographs. A faster colour film gives you more contrast, as the colours are brighter but some detail is lost.

Small-, medium- and large-format cameras

Different cameras have specific uses.

Small-format or 35 mm cameras are used mainly by journalistic, documentary and reportage photographers. They are easy to carry, quick to shoot and enable a photographer to shoot a lot of photographs quickly. This type of camera is fast being overtaken by the digital format which enables photographers to download and send pictures to clients and editors extremely quickly.

Medium-format cameras are used in editorial, portrait, fashion and advertising photography. They are good field cameras too which means they are suitable for location shooting. They produce larger negatives which means that the photographs are sharper, have more detail and are therefore more suitable for enlarging.

Large-format cameras are mainly used for architectural, landscape and still-life photography, but also sometimes editorial, portrait, fashion and advertising shoots, particularly if these photographs have to be blown up to a large size. The negatives are 4 x 5 inches which means beautifully sharp photographs but also quite a large camera which can be cumbersome to carry and always needs a tripod. This camera is used for architectural and interior photography because the back of the camera can be moved up and down allowing for perspective correction.