SLR camera lenses have specialized uses.
The single-lens reflex, or SLR, camera uses mirrors to display the image seen by the camera lens in the camera viewfinder. In other words, what the photographer sees through the viewfinder is the image that the camera will capture. SLR cameras are able to utilize a number of different lenses, which produce specific images, such as wide-angle lenses, used to take landscape, or group photographs.
Standard Lens
The standard lens, sometimes known as the "normal" lens, is a lens with a fixed focal length of 50 mm. This means that in an SLR camera, the lens is 50 mm from the film in the body of the camera. The standard lens used to come with new cameras, until it became the fashion for manufacturers to include a zoom lens with new products. The 50-mm lens is called the normal, or standard lens, because it displays an image that closely matches the image you see with the naked eye. Standard lenses are considered to be "fast" lenses, meaning that they are good at gathering light. This means that they work better in low-light situations, such as when taking pictures indoors, than zoom lenses of similar quality. The standard lens is a good choice for shooting portraits and candid pictures in low-light environments.
Zoom Lens
Zoom lenses allow you to alter the focal length of the lens while it is attached to the camera, and on an SLR, you can see the result of the zoom effect in the viewfinder. This means that you can compose pictures requiring different perspectives, without having to change the lens. For example, with a zoom lens, you can create a portrait shot of a single face in a group of people by zooming in close and framing the subject face in the viewfinder. Without changing your position, you can zoom out again to get a wider frame perspective and include the whole group. If you were using a lens with a fixed focal length for the portrait shot, you would have to change the lens for one displaying a wider angle to photograph the group. Zoom lenses are heavier than standard lenses, and they typically need more light to achieve the same quality of picture as standard lenses.
Wide-Angle Lens
Wide-angle lenses allow an SLR camera to record landscape images that include more information at the extreme left and extreme right, which cannot be captured using a standard lens. Some zoom lenses are able to achieve wide-angle focal lengths, but typically, wide-angle lenses are specialized lenses, with a fixed focal length. Lenses with focal lengths between 24 mm and 35 mm are considered to be wide-angle lenses, while lenses with focal lengths shorter than 20 mm are known as super wide-angle lenses. Wide-angle lenses do show some distortion, which is particularly visible in subjects close to the camera, but they are very useful for taking images of vast landscapes. Wide-angle lenses also have a wider depth of field, meaning that if the camera focuses on a specific subject, the area between the camera and the subject, and the area beyond the subject, where other subjects remain in focus, is wider than it would be for lenses with larger focal lengths. This makes wide-angle lenses useful for candid shots when there is no time to focus the lens precisely on the subject.
Tags: standard lens, focal length, focal lengths, fixed focal, fixed focal length, lens with, means that