The camera lens focuses light onto the film or sensor creating a crisp image. You can play with your camera settings to control what is in focus in the image. Try using focus to highlight a particular object or area in the composition. Or try having the image out of focus to create an effect. Film speed is the measure of a photographic film’s sensitivity to light. So how fast it responds chemically when it is exposed to light.
It is also referred to as “ISO” or “ASA”. Low numbers react slowly and they are used for taking shots in bright outdoor light. Higher numbers react faster and can be used in very low light. A higher film speed creates a grainier image. When using a digital camera the film speed settings are designed to respond very similarly to a film camera. Although, digital grain doesn’t look as nice. Once you have set your film speed, the next step is controlling how much light gets to the film or sensor and for how long.
This is called exposure. Exposing your film to the light. You need to use a combination of aperture setting and shutter speed to get the correct exposure. They work together so if you adjust one you should check your light meter and maybe adjust the other. Your aperture affects how much light gets in by shrinking or enlarging the hole the light travels through. This is measured in ‘F-stops’. A higher F-stop means a smaller hole which lets in less light and gives you a longer focal length or depth of field. Your shutter speed controls how long the shutter is open to let light onto the film or sensor. A fast shutter speed will let you capture high-speed action without it blurring.
If you are using a low shutter speed to let in more light then objects moving in front of the camera (or even your own hand shaking when you hold the camera) will result in a blurry image. In addition to its effect on exposure the shutter speed changes the way movement appears in the picture. Very short shutter speeds can capture high speed action images because they capture a tiny fraction of the action by opening and closing the shutter very quickly. A slow shutter speed lets light in for a long time, so fast moving objects can become blurred. Both of these options can provide fantastic opportunities for experimenting with photography. Depth of field is how deep the focus is in the shot. A large depth of field means that objects in both the foreground and the background will be in focus. A shallow depth of field will only allow a small window of focus. So if an object in the foreground is in focus the background will be out of focus.
Depth of field is controlled by the size of the aperture and the distance from the subject, and also the zoom function (if you are using a zoom lens). Different types of light have slightly different colours. This is called colour temperature. The sun is very blue when compared with incandescent light bulbs (which are yellowish). A good way to remember this is to think of a candle. The bottom (hottest) part of the flame is very blue, like the large hot sun. And the flame turns yellow as it gets cooler at the top, like smaller cooler light bulbs. Most cameras have settings where you can select which kind of light you are shooting in. Or you can manually set your white balance using the manual button. Playing with the angle that you take a photograph from can really make an image much more dynamic than if you keep the camera front-on and at eye-level.
Low-angle shots tend to make the subject look really powerful, whereas high-angle shots make the subject look more vulnerable. Over the period of a day the light changes dramatically as the sun moves across the sky. Shadows change length and the colour of the light moves from bluish through to very bright and white. Cloud cover also affects colour, brightness and shadows.