When WTF means what's the "F" number?: Lenses, Metering and panning

Lenses. To be brief, there are a lot of different lenses. A good lense is vital. Prime lenses are excellent as they are designed for a single task and have a fixed focal length (portrait photographers use a 70mm prime). Multi purpose lenses are good but cannot give the same quality of image as a prime. On the plus side a multi purpose lense does save the effort of lugging around a whole bag of separate lenses! Good lenses also tend to be expensive.
50mm prime lens gives a similar view to the human eye. Anything in the hundreds of mm being zoom/telephoto.Prime lenses are less likely to distort an image, but some distortion may occur with multi purpose lenses. Lenses with lower "f" numbers provide the best quality of image. Lenses with NR or VR are to be recommended as these minimise camera shake / vibration.

Metering.
A light meter unsurprisingly enough measures light. This is used to set the correct exposure based on the available light. Letting in too much light will overexpose an image while letting in too little with result in underexposure. Sometimes a compromise is called for when capturing an image with a bright background. Either the foreground will appear in silhouette against a "well exposed" background or the foreground wlll be correct, but the background "blown out". There are ways around this using back light compensation or by using Photoshop layering. Generally it is better to underexpose an image rather than overexpose it, as digital editing can be used to lighten dark areas, but will not be able to recover much from blown out regions.

Spot metering provides a light meter reading from a specific point. When photographing an image with a range of contrast from bright to dark then meter on the brighter part of the image (i.e. a wedding dress rather than the grooms suit).

Multi metering provides an average light reading for an area. More useful when there is less of a range in contrast.

Homework
As an exercise we were instructed to use spot metering to provide two images against a bright background. One photo to meter on the darker foreground and the other to meter on the bright background.

F8 at a 60th of a second. Spot meter on jumper.

F22 at 250th of a second. Metering on the sky

Panning and the effect of shutter speed.

Panning: Following a subject to either freeze movement or to show movement by blurring the background. A fast shutter (1/60th and faster) will tend to freeze motion. A slower shutter (less than 1/60th) will blur the background. Below are a few pictures I took today outside Kettering library. Here there's a wide expanse of pavement with steps and benches to encourage skaters to try a few tricks. These pics were taken without a tripod. The lighting was a little troublesome in that the pavement was in shade and the library wall in bright sunlight.