No lens is optically perfect. In the ideal world, every lens would produce a sharp, undistorted, evenly illuminated image that’s sharp from edge to edge. Some lenses come close, but the fact is that lens designers have to work within the limitations of the laws of physics and the glass materials they have available, and […]
A lens which can be adjusted to give a range of different focal lengths. Most lenses in use today are zooms because they're so much more versatile than fixed focal length (prime) lenses – you can adjust the framing without having to change the camera position. The disadvantages of zoom lenses are increased distortion and other aberrations, reduced maximum aperture and greater cost and weight.
The advantage of interchangeable lens cameras like DSLRs and mirrorless cameras is that you can change lenses for different kinds of photography. There are many different types of lenses, often with specific names. Lenses are usually characterised or grouped by their focal length. It might be more useful to use their angle of view instead, […]