found some generic info in a mag on different lenses and there coded meanings thought might be helpful to some people swapping teams or new to the game unfortunately i have to hand type it so if its wrong please correct me and i appolagise for punctuation in advanced. Listed in alphabetical order for easy reference if you require specific/further info wikipedia or google is probably your best bet.
AF = auto focus, nearly all lenses have this feature but theres an increasing trend for niche lens manufactures (samyang,carl ziess) to offer lenses that can be focussed manually.
AF-S = autofocus-silent, this features on nikon lenses that use a silent motor to control the autofocus.
AL = aspherical lens, all camera lenses are made up of a number of individual lenses or elements. many of these elements are spherical as if cut from a sphere. aspherical elements are less rounded and are used in some types of lenses to help minimise chromatic aberration.
APO = apochromatic, this feature on sigma lenses that use super low dispersion(sld) lens elements to reduce chromatic aberration.
AS = aspherical see AL.
ASP = aspherical see AL.
AT-X = advance technology extra, branding used on current tokina lenses.
D = a type of tokina lens that is compatible with full frame slrs.
DA = digital auto, this feature on a range of pentax lenses that (unlike some earlier ranges) don't have a manual aperture ring. they have a quick shift mechanism that enables you to override focus manually even when a lens is switched to autofocus.
DA* = star by name star by nature, the premium lens range from pentax which combines weatherproofing with the advantages of the DA range.
DC = this feature on a range of sigma lenses that are designed specifically for use with a cropped factor SLRS and which can't be used with full frame models.
DFA = this feature on the range of pentax lenses that will work with full frame 35mm film cameras, but which are also optimised for use on crop factor digital SLRs.
DG = refers to sigma lens range thats suitable for full frame SLRS(but that can also be used on crop factor models).
Di = tamrons "digitally integrated" lenses have a full size image circle so they are suitable for full frame and crop factor SLRS.
DiII = tamrons second generation digitally integrated lenses are designed for use on popular crop factor SLRS , and are not suitable for full frame models.
DO = diffractive optics , is used on a handful of canon telephoto lenses, the technology allows these long lenses to be made smaller and lighter than equivalents using conventional optics design.
DT = sony lens with a smaller image circle, designed for use on crop sensor cameras.
DX = tokinas and nikons way of marking lenses that are only suitable for crop factor or APS-C SLRS.
ED = a lens featuring extra low dispersion glass in one or more of its elements, to help correct chromatic aberration. this aberration is used by nikon,panasonic,olympus and others.
EF = electro focus, this is the name of the lens mount that canon introduced on its first autofocus SLRS back in 1987.EF lenses can be used on all canon SLRS.
EF-S = electro focus short back, introduced by canon in 2003, they have a small circle so they are only suitable for use on a crop factor SLRS. a modified mount means that they can't physically be fitted onto incompatible (i.e full frame) canon models.
EX = sigmas designation for its premium lens range.
f/X.X = the f stop number is the size of the lens maximum aperture, measured as a fraction of the focal length of the lens. on some zoom lenses there may be two apertures quoted -f4/5.6 for example. this means that the maximum aperture gets smaller as the lens is zoomed in. the maximum aperture of the lens barrel may also be expressed as a ratio so 1:4-5.6.
FA = pentax lens thats full frame compatible, and that features an old fashioned aperture ring.
FO = tokinas focus one touch mechanism allows you to switch quickly form autofocus to manual focus operation and back again by snapping the focus ring backwards and forwards.
FX = nikon or nikkor lens that compatible with its full frame SLRS as well as crop factor ones.
G = stand for gold, a designation found on top class sony lenses. its also used for current panasonic lumix compact system cameras and lenses.
HID = high index dispersion, a type of glass used in tamron lenses that helps to minimise chromatic aberration.
HSM = sigmas hyper sonic motor is used in some of its lenses to provide faster and quieter autofocus operation.
IF = internal focusing, and is found on many lenses from manufactures. the lens is constructed so that it doesn't change in length as the lens is focussed. it also means that the front element doesn't rotate- which can help with the use of some lens attachments such as petal shaped lens hoods and polarising filters.
II = second generation, a classic lens thats been updated in design by the original manufacturer.
III = third generation,
IS = image stabilization, optical camera shake reduction found in a wide number of canon lenses.
L = luxury, used to designate canons best pro lenses which have superior build quality and weatherproofing.
LD = tamron lenses that use one or more low dispersion lens elements to help chromatic aberration.
mm = millimeters, used to measure focal length of a lens.
OIS = optical image stabilisation, system used on panasonic lenses to reduce camera shake.
OS = optical stabilisation, system used on sigma lenses to reduce camera shake.
PC-E = perspective control electronic, used to designate nikons range of tilt shift lenses, which enable you to move the front elements on the lens to avoid or exaggerate lens distortion. they are commonly used in architectural photography to ensure vertical lines remain parallel in the picture.
PZ = power zoom, servo assisted zoom facility found on some panasonic compact system camera lenses.
PZD = piezo drive, a type of ultrasonic motor used in tamron lenses to provide fast quiet autofocus.
RF = rear focus, the group of elements nearest the camera are used to focus providing faster autofocus this feature is found on super telephoto lenses.
SAM = smooth autofocus motor, used in recent sony alpha lenses.
SD = super low dispersion, the glass used in tokina lenses to reduce chromatic aberration.
SDM = supersonic drive motor, pentaxs fast quiet focus motor.
SLD = super low dispersion, lens elements sigma uses to reduce chromatic aberration.
SMC = super multi coating, a seven layer coating used on pentax lenses to reduce light reflected the lens itself.
SP = super performance, a long standing tag found on top of the range tamron lenses.
SSM = supersonic motor, used for high speed autofocus in top of the range sony lenses.
SWM = silent wave motor, high speed quiet AF motor used on nikons AF-S lenses.
TS-E = tilt shift electronic, canons range of perspective control lenses , see PC-E.
UD = ultra low dispersion,type of glass used in canon lenses to reduce chromatic aberration.
USD = ultrasonic silent drive, tamrons quiet fast AF motor
USM = ultrasonic motor, fast low noise autofocus motor used by some canon lenses.
VC = vibration compensation, optical camera shake reduction system on some tamron lenses.
VR = vibration reduction, nikons image stabilisation system.
WR = weather resistant, found on certain pentax lenses.
XLD = extra low dispersion, glass used in some tamron lenses to reduce chromatic aberration.
XR = extra refractive, type of glass used in tamron lenses to reduce chromatic aberration.
ZA = zeiss alpha, range of sony lenses made by carl zeiss.