The most fundamental element any photographer should understand is aperture. The aperture is the physical opening within your lens that allows light through to the sensor (or film in an older camera). The wider the aperture opening, the more light can pass through, and vice versa.
The size of the opening, which is regulated by a series of fins encroaching from the edge of the lens barrel, is measured in so-called f-stops, written f/2.8, f/5.9 and so on, with smaller numbers denoting wider apertures. If you find this inverse relationship tricky to remember, imagine instead that it relates not to the size of the hole but the amount of each fin encroaching into the opening.
Filters and lenses
What does the ø symbol on my lens mean?
After the focal and aperture ranges, the other measurement you’ll see on most DSLR lenses is preceded by ø and describes the diameter of the screw mount on the front of lens barrel. Check this number each time you head out to buy a filter or hood as you can’t guarantee that it will be the same for each lens in your collection, even if they are all designed to be used on the same camera.
Invest in a cheap pair of lights
If you’re doing any kind of indoor photography, invest in a cheap pair of lights. Buy at least a pair, complete with tripod stands and reflectors to direct the light. Opt for continuous light rather than flash units, as they’re cheaper, easy to use and great for beginners, as you don’t have to take test shots to see how the shadows fall during setup.