Each camera body has a unique mounting interface for attaching lenses. This is called the Lens Mount. Lens mounts tell you which lenses are compatible with which cameras. For example, Canon EF-M lenses are only compatible with cameras that use the Canon EF-M lens mount.

Every camera lens produces an image circle, and the size of this circle is called coverage. The coverage of an image circle must be large enough to cover the sensor or film being used. Lens Format Coverage indicates which type of sensor or film a particular lens can cover.

Lens Type indicates whether a lens is zoom or prime (fixed) lens, as well as its general focal length and field of view.

The Fixed Focal Length of a prime lens indicates its field of view. Lower focal lengths deliver a wider field of view, while higher focal lengths indicate a narrower (telephoto) field of view.

The Focus Type of a lens is its method of focus. Manual Focus: The user adjusts the focus of the lens. Autofocus: The camera automatically adjusts the focus of the lens. Built-In Autofocus: The autofocus motor is built into the camera lens.

Maximum Aperture indicates the widest opening a lens is capable of and thus how bright or fast it is. Measured in f/stops, the size of the aperture represents how much light is passed through the lens and onto the sensor or film. The lower the f/stop, the wider the aperture.