Nikon D300 Complete Manual page 366

type lenses are the ones that enable the most features on
103
the D300
ED—Refers to a type of low dispersion glass Nikon uses in
•
many lenses. This special lens material has the primary
property of focusing different colors at the same exact spot
(regular glass tends to make different colors focus at
slightly different spots, which can create a slight prismatic
effect at hard edges in subjects). All other things being
equal, an ED lens produces better quality images than a
non-ED lens.
AF-S—Lenses marked as AF-S have a focusing motor built
•
into them instead of having to have their lens elements
moved by a driveshaft via a motor in the camera. Such
lenses focus faster and more quietly than lenses that don't
have a focus motor built in.
DX—Any lens marked DX is intended only for Nikon
•
digital cameras (other than the D3). It has an imaging
circle that's only big enough for the smaller digital sensors
(35mm film cameras require lenses with larger imaging
circles, see "Lens Differences When Used for 35mm and
D300" on page <374> for more).
• VR—This type of lens compensates for vibration and
motion, allowing you to handhold the camera and get
good images at slower shutter speeds than you otherwise
would. A 200mm lens handheld on a D300 should
normally be used at a shutter speed of 1/300 or faster, but
with VR, you may get acceptable images with a shutter
speed as slow as 1/30 second.
The 18-200mm I'm using as an example here is rather well
specified compared to the low-cost lenses that used to appear
with film cameras, and even the so-called "kit" lenses that
appeared with earlier, consumer Nikon DSLRs. Older lenses
103 Further compounding the confusion: third-party makers, such as Sigma and
Tamron don't use D and G specifications in their lens naming. The lens databases on
my site try to point out which third-party lenses are D-compatible. In general, all
recent lenses are.
Thom Hogan's Complete Guide to the Nikon D300
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