This could only be achieved by use of electronics, so each AF Nikkor lens contains what Nikon call a central processing unit CPU , although to be strictly accurate it is in fact an encoding microchip that passes this information to and fro.
It is easy to distinguish between an AF Nikkor lens and a manual focus Nikkor as the former has the 'AF' designation marked on the lens barrel and a series of electrical contact pins arranged around the rear flange of the lens mount.
The essential difference between the original series of AF Nikkor lenses and all AF lens types introduced subsequently, from the AF-D versions onwards see below , concerns the compatibility of a particular lens with Nikon's enhanced Matrix metering system known as 3D Matrix metering that was introduced during All Nikon cameras, film or digital, which support 3D Matrix metering require the focus distance information to be transmitted from the lens in order that the metering system can operate to its full potential.
If an early type AF Nikkor lens i. However, these two lenses are not compatible with any of the current Nikon AF cameras. To provide full functionality with the 3D Matrix metering system that has been incorporated in Nikon camera models introduced since , which uses the focus distance information as a component in calculations for both ambient light and flash exposures Nikon introduced the AF-D series Nikkor lenses.
Although externally these lenses look very similar to the earlier type of AF Nikkor the internal microchip performs the additional function of communicating the focused distance of the lens to the camera body, hence the 'D' D - distance designation.
Cameras compatible with Nikon's 3D Matrix metering system use this information to improve the accuracy of their built-in through-the lens TTL ambient and flash exposure metering systems. AF-D lenses can be identified by the 'D' designation in the description of the lens; this is marked on the lens barrel, and generally it is also shown as a suffix to the lens aperture value, which is also displayed on the lens except in the case of AF-G lenses. To improve the focusing speed of their autofocus lenses, particularly long focal length, wide aperture telephoto types, Nikon introduced the AF-I I - internal series of Nikkor lenses.
Rather than using the focusing motor built-in to the body of an AF Nikon camera, which relies on a mechanical drive shaft link between the camera and lens to operate the focusing action, the AF-I type Nikkors have a coreless electro-magnetic focusing motor built in to the lens, which improves both the speed and accuracy of autofocus, significantly.
All are clearly identified by the designation shown on the descriptive plate attached to the barrel of each lens that also displays the serial number of the lens. The successor to the AF-I type Nikkor lens uses an enhanced version of the internal focusing motor, which converts ultrasonic sound waves to generate a rotational energy to drive the focusing action. This type of motor offers even greater speed and accuracy of autofocus action combined with near silent operation.
Note: Nikon's choice of the AF-S designation is somewhat confusing since the same designation is used consistently throughout Nikon literature to denote the Single-servo AF focusing mode available in all AF Nikon cameras.
Initially these lenses appeared as entry level models with a specification and price point intended for the consumer market, because they offered an number of benefits including being simpler to use by less experienced photographers, lighter, easier to construct, and therefore cheaper to mass produce. Note: Earlier Nikon camera models that lack the ability to set the aperture value from the camera body require a Nikkor lens with an aperture ring to obtain full compatibility with all the exposure modes available on the particular camera in use.
Optimized for the DX format Nikon makes two different types of DSLR camera bodies—those that have a built-in focus motor, and those that don't.
The cameras that don't have a focus motor built-in need to use a lens that has a focus motor built-in to it. On several Nikon DSLR camera bodies, the focus motor is in the camera and a series of gears drives the lens' focusing mechanism, which allows the lens to focus.
This enables high-speed autofocusing that's extremely accurate and super quiet. Or, in other words, because AF-S NIKKORs have the focus motor built into the lens, they can be used on any current Nikon camera body, whether the body has a focus motor or not, because the lens itself controls the focusing function. Consumer level Nikon digital SLR cameras are designed without built-in focus motors, which allow them to be smaller and lighter than the larger, more professional models.
But what if you own one of the aforementioned consumer level camera bodies and really want to use an AF lens. You need to know if your camera can accept the lens—and the answer is yes. You will have to manually focus the lens, using the focus ring on the lens barrel. The electronic rangefinder, which is visible in the lower left portion of the viewfinder, will confirm that your subject is in focus. Rotate the focus ring on the lens and when it lights up green, the subject is in focus.
Older lenses have switches on the lens barrel for turning VR on and off, as well as switching between manual focus mode and AF mode. Select newer NIKKOR lenses incorporate an electromagnetic diaphragm mechanism in the lens barrel to provide highly accurate electronic diaphragm or aperture blade control when using auto exposure during continuous shooting, especially when shooting at high frame rates.
This is different from G or D type lenses, in which the diaphragm blades are operated mechanically. One of the great aspects of Nikon's camera systems is that most of the legacy lenses—those that you may have used with your film-based Nikon SLR camera—can be used on your digital SLR camera. What if you've got older lenses that you used to use with a Nikon film-based SLR camera—well you can use those lenses as long as they were made after That's when Nikon began manufacturing AI lenses.
AI stands for "Automatic Maximum Aperture Indexing" system, which is the mechanical system for coupling the lens to the camera's exposure system. Price-Match Guarantee. Instruction Manuals. Think Tank Camera Bags. Grays Merchandise. Ordering Information. Gift Certificates. Second-hand Equipment. Autofocus Nikkor Lenses. Nikon Digital Cameras. Nikon 35mm Film Cameras. Nikon Mirrorless. Manual Focus Nikkor Lenses.
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