On photography forums I see a lot of confusion about what is meant by prime lenses, zoom lenses, and telephoto lenses in particular.
- A zoom lens is able to change its focal length, i.e. to zoom in and out. This does not necessarily mean that it is a telephoto lens.
- A prime lens has a fixed focal length. It can be any focal length.
- A telephoto lens has a long focal length and high magnification, and “sees” a narrow field of view. It can be either a zoom lens or a prime lens.
- A wide angle lens has a short focal length and low magnification, and “sees” a wide field of view. It can be either a zoom lens or a prime lens.
This table shows the crossover of these lens types, with some typical examples.
|Zoom lens||Prime lens|
|Wide angle lens||10-20mm||20mm|
So as you can see, all lenses are either prime or zoom, and also fall into a category of telephoto, normal or wide depending on their focal length. Check out which lenses count as which category.
Just to mix things up a bit, some zoom lenses span two of the categories, so an 18-135mm lens would be a normal-to-telephoto zoom lens.
Hope this helps someone!