Camera lenses vary greatly, as do the various types of photographic subjects you might be interacting with, and the myriad types of camera mounts and lenses.
Certain fields of view (focal length) are more suitable for different subjects and some camera lenses even have particular features to suit individual requirements, such as a macro feature to have a closer focus for insects, plants, etc. Every type of photography favors a length of some kind.
So not only is it hard to know which camera lenses are best for your needs, but you also need to know which lenses will fit your camera or photographic system. This is due to what is called the lens mount.
In short, each manufacturer has their own (not entirely true, but a good starting point)… Many lens mounts exist, including the widely established Canon EF/EF-S lens mount system (Canon EF and Canon EF-s ), Nikon’s wide range of lenses and then the Pentax, Sony/Minolta, Four Thirds and the new Micro 4/3rds, Sony E-Mount and Samsung’s NX fit. then of course Sigma, who makes lenses for everyone else’s cameras, has their own fit too. Through this there are classes of glass for consumers and professionals.
For the types of photography, the type of lens is considered. With this, there are a few categories of lenses from the specialist Tilt and shift, Macro and then wide angle, standard and telephoto lenses. Below is a list that is by no means final.
Macro: – Insects and plants
TSE – Architecture
Wide Angle – Views, Documentaries and Landscapes
Standard – Portrait, Events, Editorial, Photojournalism, Wedding
Telephoto: sports, wildlife, events, journalism
For a MASSIVE and exhaustive list of currently available lenses and their photography applications, check out the Park Cameras Lenses and Photography Types article.