There is an excellent range of SLR lenses available for Canon, Nikon, Sigma and Sony fit cameras, plus a whole range of other lens manufacturers. This choice is now met with a list of technical acronyms, some of which mean exactly the same thing. This list of abbreviations is now getting rather lengthy and to some rather confusing.

Canon have theirs as have Nikon, then Sigma join in with a set all of which largely mean the same thing.

Short of memorising his list there is little you can do except rely on rely on the kindness of someone like Park Cameras who will happily tell you if you ask them or use a webpage like this as reference.

Below Park Cameras have compiled a list of terms and meanings what it menas the lens will do or prevent.

General DSLR lens abbreviations and acronyms

General acronyms, abbreviations and terminology used to describe camera lenses

There are a couple of common terms used within photography to describe SLR lenses. These are used across all lenses but these are simple to understand and they relate to performance.

Focal length
24-70mm. A lens which covers an area of 24mm (relatively wide) zooming in to 70mm.

Maximum aperture
eg f/2.8 or f3.5 - 5.6

If a lens has one number then that is the lenses maximum aperture across its entire focal range (lower numbers have larger apertures and are faster, shorter depth of field but are far more expensive). If a lens has two numbers then the first one eg f/3.5 is its maximum aperture at its widest and the smaller number is its maximum aperture at its longest.

AF/MF. Switch between Auto Focus and Manual Focus

Canon Lens Abbreviations and acronyms

How Canon describe their EF and EF-s or L series lenses

Canon produce an wide range of lenses for EOS cameras which married with Sigma, Tamron and Tokina gives Canon owners a collosal choice of  Canon Fit SLR Lenses. The abbreviations used by Canon are as below.

EF: Electronic Focus. Lens mount fitting the entire Canon DSLR system.

EF-S : As above but only fitting on a Canon's APS-C sized digital SLRs such as the 20D, 30D, 40D, 50D. 60D and 300D, 350D, 400D, 450D, 500D, 550D and 600D. The S stands for "short back focus," meaning that the back of the lens is much closer to the CMOS (CCD) than with EF lenses.

USM : USM is Ultrasonic autofocus. There are two types is USM. Micro-USM (a direct replacement for the systems on older FD motors) and a faster 'Ring USM' which includes manual overide.

DO: Diffractive optics. A technology which allows Canon to make lenses with long focal lengths without the normal increase in physical size.

TS-E : Tilt-shift lens for architectural photography. altering the perspective of converging lines and depth of field.Much like using a style 'Sinar' camera.

L Lenses : Canon's professional lenses. Refers to their optical quality not necessarily anything specificaly functional. Usually white in colour. always havng a red ring around the end. 

MP-E : Macro Photo Electronic are for macro work through the use of electronic aperture control.

IS : Image Stabilisation, A system designed to reduce shake. Nikon have their own version called VR (Vibration Reduction) and Sigma use the term OS (Optical Stabilisation).

Nikon Lens Abbreviations and acronyms

How Nikon describe their lenses

Nikon also produce a significant range of lenses with their own abbreviations (as below). Sigma, Tamron and Tokina also make Nikon Fit SLR Lenses making the selection almost equally as wide.

AF DC_ Nikkor Lenses : Defocus-image Control that adjusts the spherical aberration and therefore the blur giving rounded defocussing effect often used in portraiture.

CRC (Close-Range Correction) : Used in fisheye, wide-angle, Micro, and limited medium telephoto, offering high quality at closer focusing distances.

DX Nikkor : As with Canon EF-S lenses, DX lenses are optimised for cameras with smaller sensors. They will fit on other cameras but this is not recommended.

ED: Extra-low Dispersion glass. Gives superior sharpness and optimal colour by correcting the diferences between the angles that blue and red light travel in as they pass through the lens.

IF : Internal Focusing. the focussing mechanisms are within the lens ensuring the lens remains the same size as focal length is changed.

Macro : Lens designed to capture subjects closer to the lens.

G : No aperture ring. Aperture is adjusted electronically by the camera body.

Nano Crystal Coat : non-reflective coating for clearer images with increased detail by reducing reflection from inside the lens.

VR: Vibration Reduction : Nikon's version of Canons IS system, designed to cut down on the effects of hand shake.

PC-E: Perspective Control similar to Canon's Tilt and Shift Lenses.

RF: Rear Focusing. Uses the rear group of lens elements to focus giving faster and smoother AF.

Silent Wave Motor : Silent Auto focussing (as Canons USM)

Sigma Lens Abbreviations and acronyms

Acronyms for Sigma lenses

EX : Pro lenses offering highest optical quality.

DG : Like EF lenses, DG lenses are designed to be used with both full frame and cropped frame sensor cameras. Sigma DG lenses also include additional coatings to reduce reflection.

DC: Short for Digital Crop. They canonly be used on cropped frame cameras. they are also lighter and often less expensive.

ASP: Aspherical lens. Smaller than normal lenses.

APO: Apochromatic lenses with low dispersion glass to limit chromatic aberration.

OS: Optical Stabilisation. As Canon IS or Nikon VR.

HSM: Hypersonic Motor. As Canon's USM system.

RF: Rear focus. The rear elements are moved for quieter and faster focusing.

IF: Inner focus lenses move the middle lens elements, ensuring the lens remains the same length throughout its focal range. This is useful on longer shots as it reduces hand shake.

DF: Dual focus. Does not rotate while autofocusing.

Conv: Can be used with Sigma teleconverters.

Tamron Lens Abbreviations and acronyms

Acronyms for Tamron Lenses

ASL : Aspherical Glass.

AD : Anomalous Dispersion. Reduces chromatic aberration..

Di : As Sigma DG lenses.

Di II : For APS-C frame sized cameras (as Canons EF-S).

IF : Internal focus. Lens stays the smae length reducing hand shake at longer telephoto lengths

LD : Low Dispersion Glass to reduce chromatic abberation

Macro : For focusing on nearer subjects

SP : Super Performance. Tamron's best lens range.

XR : Extra Refractive Glass for improved optical results.

VC: Vibration Control as found on Canon's IS, Sigma's OS and Nikon's VR