A lens or camera lens is an optical lens or assembly of lenses that, when used in conjunction with a camera body, allows photographs to be taken on film stock.
The choice of lens is one of the most important decisions when taking a photo. It is crucial for the look, the image quality and of course especially which part of the image can be seen. As with the camera and film stock, in analog photography you have a wide range of possible candidates. Of course, only if it is not a camera with a built-in lens that cannot be changed.
The name of a camera lens usually already gives information about the most important technical parameters and, if applicable, functions. The focal length is given in millimeters. It provides information about the angle of view when using the lens. Here, however, the size of the recording format also plays a decisive role. In general, the lower the number, the wider the angle of the lens. The wider-angled the lens, the higher the angle of view and the more that fits into the photo.
Depending on the focal length / angle of view, the lens can be placed in one of the three categories in the archive. If the angle of view is less than 60 degrees in the diagonal, it is a wide angle lens. If not, it is a standard lens or a telephoto lens. Telephoto lenses have a small angle of view and allow pictures of distant subjects.
The second parameter is the aperture. The number indicates how large the maximum aperture can be. The lower the number, the larger the aperture. The larger the aperture, the more light can fall on the film. Lenses with a large aperture are also called fast.
Other abbreviations in the lens name can provide information about the coating of the glass or, if applicable, an autofocus function.
