- First things first: why do you want one?
- How digital cameras work
- Photo Terminology
- Camera features
- Image Compression
- Questions to ask the retailer
As a PC user you might be under the impression that mastering digital photography is simpler than film photography. In fact, to get the most out of a middle or top of the range digital camera, you need to know exactly the same fundamentals about photography. For those of you who aren't too familiar with photo terminology, here are some quick explanations to help.
Aperture: The aperture of a lens is related to its diameter and is a measure of how much light the lens allows in. Altering the aperture, therefore, is an important means of controlling the exposure recorded within the image. Aperture is measured in f-stops, although, confusingly, the larger the aperture, the smaller the f-stop.
f-stop: A measure of how much light a lens lets in. More precisely, it's the ratio of the diameter to the focal length. So a lens with a true focal length of 20mm, which is 10mm in diameter, has a maximum aperture of f/2. An implication of this is that a zoom lens will have a smaller maximum aperture when it is zoomed in.
Shutter speed: This is the length of time light is allowed into the camera when a photo is taken. Commonly, shutter speed can be varied from 1/1000 second to a few seconds. One of the most important things to note about shutter speed is its effect on movement. With a slow shutter speed, typically, less than 1/60th of a second, a moving object will be portrayed as blurry. Faster shutter speeds allow the user to capture a moving object much more clearly - even droplets of water in a fountain will appear to be frozen in mid-air.
Focal length: The focal length is a property of the lens which dictates the amount by which it magnifies the scene. The zoom control on higher-end cameras is the means by which the focal length is altered. Commonly, the focal length of a digital camera is given as a 35mm equivalent because so many people are familiar with 35mm cameras. The actual focal length will be shorter, because the CCD is smaller than 35mm film.
You should also be aware that changing the focal length affects perspective. A short focal length exaggerates perspective; a long focal length shortens it.