Pixiq

The designation of Nikkor lenses, particularly modern autofocus types, is peppered with initials. Here is an explanation of what some of these stand for:

AF: These lenses are the predecessors to the later D- and G-type designs. They have a conventional aperture ring but lack an integral focusing motor and do not communicate focus distance information to the camera.

AF-D: These lenses have a conventional aperture ring and an integral electronic chip that communicates information about lens aperture and focus distance between the lens and the camera body. Nikon refers to this chip as a central processing unit (CPU), but to be strictly accurate it is an integrated circuit. A “D” appears on the lens barrel after the maximum aperture value.

AF-G: These lenses have no aperture ring and are only compatible with Nikon cameras that allow the aperture value to be set from the camera body. They contain an electronic chip that communicates information about lens aperture and focus distance between the lens and the camera body, similar to the D-type lenses. A “G” appears on the lens barrel after the maximum aperture value.

AF-I: The predecessor to the AF-S lens type; these lenses also have an integral focusing motor.

AF-S: These lenses use an integral silent-wave motor (SWM) for focusing; alternating magnetic fields drive the motor, which moves lenses elements to shift focus. This system offers the fastest autofocusing of all AF Nikkor lenses. Most AF-S lenses have an additional feature that allows the photographer to switch between autofocus and manual focus, without adjusting any camera controls, by simply taking hold of the focus ring. “AF-S” appears on the lens barrel.

Ai: These lenses feature the Automatic-Indexing (Ai) coupling on the lens mount, which was introduced in 1977. Virtually all AI type lenses feature the meter coupling prongs that protrude from the lens barrel at the rear edge of the lens, plus a ridge on the aperture ring that indicates, via a mechanical link, the aperture setting relative to the maximum aperture value of the lens, together with a post on its lens mount flange that relays the value of the maximum aperture. All manual focus Nikkor lenses designated as AI, Ai-S, and Series E are classified as Ai type lenses. In 1981, a further modification to the Ai lens mount was introduced that featured two mechanical modifications to support the automatic and semi-automatic exposure systems that were introduced a couple of years later with the Nikon FA camera.

DX: These lenses have been specially designed for use on Nikon digital SLR cameras. They project a smaller image circle than lenses designed for 35mm format cameras, and the light exiting their rear element is more collimated (actually parallel) to improve the efficiency of the photo diodes (pixels) on the camera’s sensor. “DX” appears on the lens barrel.

ED: To reduce the effect of chromatic aberration, Nikon developed a special type of glass known as Extra-low Dispersion to bring various wavelengths of light to a common point of focus.

IF: To speed up focusing, particularly with long focal length lenses, Nikon developed their internal focusing (IF) system. This moves a group of elements within the lens so that it does not alter the length of the lens during focusing, and prevents the front filter mount from rotating, thus facilitating the use of filters such as a polarizer.

N (Nano Crystal Coat): A specialized lens coating that is applied to the surface of some lens elements to help reduce the level of light reflection, improving overall image quality. An “N” appears on the lens barrel.

Non-CPU: Nikon uses the term “non-CPU” to describe any Nikkor lens lacking the components and electrical connections that enable communication of information between the lens and the camera body. With the exception of the PC-E 24mm f/3.5D, PC-E Micro 45mm f/2.8D, PC-E Micro 85mm f/2.8D, PC-Micro 85mm f/2.8D lens, and Ai-P type Nikkor lenses, all manual focus Nikkor lenses are non-CPU types.

Micro-Nikkor: The name given to specialized lenses designed for close-up and macro photography; the optical formula of these lenses is optimized for close focusing.

PC-E: A special type of lens that offers the ability to shift and tilt the lens relative to the plane of the camera’s sensor to control perspective and position of the focus plane, respectively. “PC-E” appears on the lens barrel.

VR: Vibration Reduction (VR) is Nikon’s name for a sophisticated technology that enables a lens to counter the effects of camera shake and other vibrations. A set of built-in motion sensors that cause micro-motors to shift a dedicated set of lens elements is used to improve the sharpness of pictures. “VR” appears on the lens barrel.