Knowing Nikon Lens Nomenclature
Nikon's lens nomenclature can be confusing for new DSLR users. AF, IF, AF-S, VR, D, G, DX, N - What do these letters mean on your lens?. Read below for an explanation :-
An example of features on a D90 lens
AF = Auto-Focus
These lenses have a unique mechanical coupling which attaches to your Nikon DSLR, which then moves the lens. There are no motors in AF lenses, so your DSLR will determine the speed at which it focuses. On a side note, the Nikon D40 , D40x, D60 and D5000 do not have internal motors themselves to use the coupling device on non-motorized lenses. Your DSLR must have an internal motor itself in order to use the auto-focusing feature of lenses which do not have their own motors to drive the focusing system. So, for example, only AF-S lenses will work with a D40, D40x, D60 and D5000.
AF-S = Auto-Focus + Silent Wave Technology (Ultrasonic Technology)
This is a step-up from your ordinary AF lens. Ultrasonic motors are used in these kinds of lenses, making the movements of the lens element groups, virtually silent. Ultrasonic waves are used to move the lens elements back and forth. AF-S lenses are also famous for lighting-fast focusing. Again, this is becaue of the ultrasonic technology.
D = Distance
The "D" on Nikkor lenses, is in reference to distance. An internal encoder is connected to the lens focusing ring, and transmits the shooting distance information to the camera automatically. 10-segment Matrix Metering is an example of what a "D" lens can do when attached to your D-series DSLR. A Lens without a "D" means you will not be able to meter with your D-series DSLR.
The D indication can be found on older lenses such as some of the 50mm lenses above
DX = 24mm x 16mm
This type of lens is specifically engineered for the DX format DSLR, by making a smaller image circle lens. Nikon's 24mm x 16mm imager size in their D-series cameras, are referred to as a "DX" format. This is why Nikon has released lenses with the DX name.
ED = Extra-low Dispersion
The farther you zoom, the more CA (Chromatic Aberration) is apparent. ED Lenses are made to reduce CA and are used in the more expensive zooms. Chromatic Aberration happens due to basic physics of light. A lens will not focus different colors in the exact same place, because each color has its own wavelength (Blue focuses nearer than Green or Red wavelengths). Thus, you need different lens elements to focus at specific color wavelengths. This is why some lenses are so expensive, and have multiple lens elements in them. An example of CA in a photo would be taking a photo pointed at a subject that has several edges, such as leaves on a tree, or a building with many different architectual edges poking out. CA would be prevalent if you notice purple-ish "blooms" around the edges of the subject.
G = No aperture ring on lens
All new lenses released by Nikon do not have an aperture ring. The G denotes the absence of a manual aperture ring. The aperture of the lens can only be set using the camera body.
IF = Internal Focusing
Internal Focusing on certain kinds of lenses, particularly telephoto lenses, allows for a much more balanced lens when shooting. The lens focuses internally, needing no more room to focus than the length of the lens itself, so you don't have to worry about buying a 12" lens and ending up with a 24" lens after zooming completely in on a subject, and having to counter-balance the effect.
VR = Vibration Reduction
VR (Vibration Reduction) lenses are beginning to appear much more often from Nikon. What this technology does, is allow for lower shutter speed photos, without the blur that is normally associated with it. The 80-400VR was the first to use this technology. Most new DX lenses from Nikon include VR.
N = Nano
The Nano crystal coating applied to an element of the lens to effectively reduce flare and ghost.
Pro tip by Alan Bernard