Nikon Autofocus Lens Terminology

The Nikon F-Mount was first introduced in 1959, and has since become the mount used on all Nikon SLR cameras.  Over that time, Nikon has amassed one of the largest collection of lenses available.  However, as new technology is introduced and new features are incorporated, sometimes differentiating between one lens and another becomes tricky.  Nikon has developed a series of abbreviations and terms to help identify one model lens from another, as well as tell consumers what features an individual lens has.  This article will discuss and help you identify some of the more commonly used terms and abbreviations.

G-Type Nikkor:  G-Type Nikkor lenses are very similar to D-Type in that they communicate distance to subject, but do not have an aperture control ring.  Because of this they are mainly intended for use on later model film and digital bodies, where the aperture is adjusted via the camera's command dials.  Because G-Type lenses communicate distance information, they are also considered D-Type lenses.  However, only one designation is ever listed, either G or D, never both.

D-Type Nikkor:  D-Type Nikkor lenses have a computer chip in that allows the lens to communicate subject distance to the camera.  Many of these lenses have an aperture control ring, allowing reverse compatibility with older film cameras, while still working well on many DSLR's.  They are especially useful while recording movies because of the manual aperture control.  However, when used on a DSLR, the aperture ring needs to be locked in at the smallest possible aperture (usually highlighted in orange) to prevent a communication error.

 DX Nikkor:  DX-Nikkor lenses are designed and optimized for use on Nikon DSLR's that do not utilize a full frame (FX) sensor.  The DX sensors, due to their smaller size, do not require as large of an image circle to be projected by the lens.  Because a smaller image circle is utilized, these DX optimized lenses can be made with less materials, making them smaller, lighter, and less expensive.  Although the mount is the same, if attached to a FX series body, the body will switch to a "DX mode" which uses less resolution and introduces a 1.5x magnification factor.  This can be overwritten but will result in significant vignetting.

Vibration Reduction:  Vibration Reduction is a lens stabilizing technology that helps reduce image blur caused by camera movement.  Depending on the lens, Vibration Reduction can provide anywhere from 2-4 stops of additional hand hold ability compared to lenses without VR.

Silent Wave Motor:  The Silent Wave Motor uses ultrasonic traveling waves, converted to rotational energy, to focus the lens.  Other auto focus lenses are driven by a motor in the camera, linked by a gear system to the lens.  The Silent Wave Motor is faster, smoother, and significantly quieter than its gear driven predecessor.  On some newer, entry level DSLR's (D40, D40x, D60, D3000, D5000, D3100, D5100) do not have the motor in the body, and therefore require an AF-S lens to auto focus.

ED Glass: Extra-low Dispersion (ED) and Super ED glass help to correct chromatic aberration, or color fringing, caused when different wavelengths of light don't hit the sensor at the same point.  Because of the positive benefits of this glass element, it is utilized in a large percentage of Nikon lenses and one of the more common symbols on the lenses in use today.

Nano Crystal Coat: Nano Crystal Coatings are anti-reflective coatings that are attached to the elements at the molecular level.  These coatings minimize ghost and flare effects caused by red light, as well as light that enters the lens diagonally.  The result is obviously clearer images.

Internal Focusing: Lenses that have internal focusing do not have any externally moving elements or parts when the lens is focusing.  It is particularly useful when using lens hoods and/or polarizing filters.

Manual Auto Mode: Standard on many mid-level and high end zoom lenses with an AF-S motor, the Manual Auto Mode allows you to switch from auto to manual focus with very minimal time delay.  The change is nearly instant, allowing you to fine tune focus manually on the fly.

Auto-Priority Manual Mode: This mode is very similar to the Manual Auto Mode, but with altered sensitivity to the manual override.  This is important because it prevents instances of the lens switching to manual focus inadvertently.

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