Does your lens has more letters after its name than a retired rocket scientist. What do all these lens markings mean?
You can refer to a lens simply by the name of the manufacturer, the focal length, and its maximum aperture – a Sigma 70-300mm f/4-5.6, say, or Canon 50mm f/1.4. But as lenses have often evolved from decades of development, they usually have a line of additional letters after their names, stamped on the barrel or printed on the boxes.
Some lens markings are about manufacturer branding – defining a more recent range, or a lens that’s built to higher standards than another. Others are to do with the optics themselves, and to highlight specific technologies used in the lens construction.
In the jargon-busting guide below, we’ll translate these lens markings for you.
The ultimate guide to understanding lens markings
AF Stands for autofocus. Nearly all lenses have this feature, but there’s an increasing trend for niche lens manufacturers (such as Samyang and Carl Zeiss) to offer lenses that can only be focused manually.
AF-S Stands for autofocus-silent. This features on Nikon lenses that use a silent motor to control the autofocus.
AL Stands for 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 Stands for apochromatic. This features on Sigma lenses that use super-low dispersion (SLD) lens elements to reduce chromatic aberration.
AS Stands for aspherical (see AL).
Asp Stands for aspherical (see AL).
AT-X Stands for Advance Technology Extra – the branding used on all current Tokina lenses.
D A type of Tokina lens that’s compatible with full-frame SLRs.
DA Stands for Digital Auto. This features 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 the 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 features on the range of Sigma lenses that are designed specifically for use with crop factor SLRs, and which can’t be used with full-frame models.
DFA This features 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 This refers to the Sigma lens range that’s suitable for full-frame SLRs (but that can also be used on crop-factor models).
Di Tamron’s ‘Digitally Integrated’ lenses have a full-size image circle, so they are suitable for full-frame and crop-factor SLRs.
Di II Tamron’s 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 optical designs.
DT Sony lens with a smaller image circle, designed for use on crop-sensor cameras.
ED A lens featuring Extra-low Dispersion glass in one or more of its elements, to help correct chromatic aberration. This abbreviation is used by Nikon, Panasonic, Olympus and others.
EF Standing for 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-focus lenses were introduced by Canon in 2003. They have a small image circle so they are only suitable for use on crop-factor SLRs. A modified mount means that they can’t physically be fitted onto incompatible (ie full frame) Canon models.
EX Sigma’s designation for its premium lens range.
f/X.X The f-stop number is
the size of the lens’s maximum aperture, measured as a fraction of the focal length of the lens. On some zoom lenses there may be two apertures quoted – f/4-5.6, for example. This means that the maximum aperture gets smaller as the lens is zoomed in. The maximum aperture on the lens barrel may also be expressed as
a ratio – so 1:4-5.6.
FA Pentax lens that’s full-frame compatible, and that features an old-fashioned aperture ring.
FO Tokina’s Focus-One-touch mechanism allows you to switch quickly from autofocus to manual focus operation, and back again, by snapping the focus ring backwards and forwards.
FX A Nikon, or Nikkor, lens that’s compatible with its full-frame SLRs, as well as crop-factor ones.
G Stands for Gold – a designation found on top-class Sony lenses. It’s also used for current Panasonic Lumix compact system cameras and lenses.
HID Stands for High Index Dispersion, a type of glass used in Tamron lenses that helps to minimise chromatic aberration.
HSM Sigma’s Hyper Sonic Motor is used in some of its lenses to provide faster and quieter autofocus operation.
IF Stands for Internal Focusing, and is found on many lenses from many manufacturers. The lens is constructed so that it doesn’t change in length as the lens is focused. 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.
iFn Stands for i-Function, a feature of Samsung NX cameras which allows photographers to access a number of key camera settings via a button and ring around the lens.
II This stands for second-generation – a classic lens that’s been updated in design by the original manufacturer.
III Stands for third-generation.
IS Stands for Image Stabilization – optical camera shake reduction found in a wide number of Canon lenses.
L Stands for Luxury, and is used to designate Canon’s best pro lenses, which have superior build quality and weatherproofing.
LD This features on Tamron lenses that use one or more Low Dispersion lens elements to help reduce chromatic aberration.
mm Stands for millimetres – used to measure the focal length of a lens.
OIS Optical Image Stabilisation – the system used on Panasonic lenses to reduce camera shake.
OS Optical Stabilization is
the system used on some Sigma lenses to reduce camera shake.
PC-E Stands for Perspective Control-Electronic. Used to designate Nikon’s 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 Stands for Power Zoom,
a servo-assisted zoom facility found on some Panasonic compact system camera lenses.
PZD Stands for Piezo Drive,
a type of ultrasonic motor used in Tamron lenses to provide
fast, quiet autofocus.
RF With 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 Stands for 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, Pentax’s fast, quiet focus motor.
SLD Super-low dispersion – lens elements in Sigma lenses that reduce chromatic aberration.
smc Stands for 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,
the high-speed quiet AF motor used on Nikon’s AF-S lenses.
TS-E Tilt-shift Electronic – Canon’s range of perspective control lenses (see PC-E).
UD Ultralow dispersion – type of glass used in Canon lenses to reduce chromatic aberration.
USD Ultrasonic Silent Drive, Tamron’s fast, quiet 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, Nikon’s 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. It can bend light at bigger angles than normal glass, helping make the overall size of a lens smaller.
ZA Zeiss Alpha – a range of Sony lenses made by Carl Zeiss.
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