Lens Types

Wide-angle lens
Wide-angle lenses allow you to emphasize perspective by getting in close to your subject. This makes them great for sweeping landscapes where objects in the foreground appear much larger and the horizon appears much further away. A wide angle lens has a focal length wider than 40mm (35mm equivalent). Anything wider than 21mm is classed as ultra-wide. Wide angles are essential for interior photography where space may be tight and also architecture or expanses of land where the subject is huge and needs the wide-angle to get everything in frame.

See our guide to using wide-angles lenses here

Standard lens A standard lens is so called because it gives roughly the same magnification as the human eye, which is actually around 43mm. This lens used to be supplied with all film cameras when you bought a camera, but once zooms appeared the standard lens took a back seat. It's often preferred by purists because it has three key features. First is speed. A standard lens will have an aparture of f/2 or faster. Most of the modern standard lenses are either f/1.7 of f/1.4. There are also a few f/1.2s and f/1s around too. Secondly the simple construction allows a standard lens to be smaller and lighter making it east to carry around. Third is the fact a standard gives roughly what the eye sees so can ensure what you photograph appears more natural and doesn't place emphasis on what appears to be unnatural perspective.

See this article on using standard lenses here