If it was a car, it would be a GTI…
Alphabet soup
Like cars, lenses tend to have a lot of letters and numbers printed on them, but what do they all mean? If you’re feeling discombobulated, here’s a quick guide to the markings on Canon, Nikon and Sony lenses.
General
Whatever company makes them, all lenses have certain markings in common. Some show the type of lens while some show the different settings on the controls. Here’s a list of the main ones and what they all mean.
A
A stands for Automatic. This means the lens will use the autofocus system.
A/M
A/M stands for Automatic/Manual. These lenses allow manual focus override, but the focus ring is less sensitive to avoid accidental refocusing.
ED
ED stands for super Extra-low Dispersion and denotes lenses that have glass elements to compensate for chromatic aberration.
FL
FL stands for FLuorite. Fluorite elements weigh less than regular optical glass.
Focal Length
This is usually marked in millimetres (mm), but it may be paired with the maximum aperture. For example, 2.8 / 100 means the focal length is 100mm. If it’s a zoom, the range will be shown, such as 70-200mm.
I, II or III
Roman numerals at the end of a lens name show that it’s the second version of that lens. It doesn’t refer to the previous letters, such as VR on a Nikon lens, so it doesn’t mean the lens necessarily has VR II, the second version of the VR system.
Lens Diameter
The diameter of the lens is normally shown as a number after the Ø symbol, such as Ø72. This just means you need 72mm filters to fit on the lens.
Lock
Most zoom lenses have a zoom lock slider that lets you pack them away or carry them without the lens getting longer. This is called ‘zoom creep’.
M
M stands for Manual. This means the lens can only be focused manually by turning the focus ring.
M/A
M/A stands for Manual/Automatic. These lenses allow manual focus override by simply turning the focus ring.
Macro
If the lens has the word MACRO printed on it, it means it’s a macro lens capable of focusing at short distances and normally at a magnification ratio of at least 1:1. Nikon calls these Micro NIKKOR lenses.
Magnification Ratio
Macro lenses will often show the magnification ratio. This normally at least 1:1 (or 1x), which means any dimension of the image on the sensor is at least as long as the same dimension of the subject in real life. If it’s less than that, such as 1:2 (or 0.5x), it means the distance is only half as long—which means the whole subject is only a quarter of the size.
Maximum Aperture
The widest or maximum aperture of the lens is shown as a ratio, such as 1:2.8. The first number is always 1, and the second number is shown either as a whole number or a number with one decimal place. Lenses manufactured in Europe might use the comma rather than the decimal point, as in 1:2,8.
If it’s a zoom lens, the maximum aperture might change as you zoom in and out. In that case, the second number is shown as a range, such as 1:4.5-5.6.
Minimum Focusing Distance
This is shown in metres and feet with a / between the two values, such as 4.5m / 14.8ft.
PL
PL stands for Positive Lock and denotes a lens with a PL-type bayonet mount.
PZ
PZ stands for Power Zoom.
Canon
Here’s a list of all the markings you might find on a Canon lens.
ASC
ASC stands for Air Sphere Coating, which reduces lens flare and ghosting.
AFD
AFD stands for Arc Form Drive, which is the name of Canon’s first autofocus motors.
BR
BR stands for Blue spectrum Refractive, which is a lens element made of organic optical material that corrects colour fringing.
CN-E
CN-E stands for CiNema EOS and denotes lenses in the professional cinematography range.
CINE-SERVO lenses are CN-E lenses with removable hand zoom controllers.
Compact Servo lenses are mid-range CN-E lenses.
KAS S lenses are compact CINE-SERVO lenses.
DO
DO stands for Diffractive Optics and denotes lenses that have special elements to make them more compact. They usually have a green ring around the front of the lens.
DS
DS stands for Defocus Smoothing and denotes a coating that leads to smoother bokeh.
EF
EF stands for Electronic Focus and denotes Canon’s oldest lens mount for DSLR cameras.
EF-M
EF stands for Electronic Focus Mirrorless and denotes Canon’s dedicated lens mount for its compact system cameras, the EOS M-series.
EF-S
EF-S stands for Electronic Focus-Small. It denotes lenses that have a smaller image circle as they’re designed for use with Canon’s APS-C DSLRs that have a 1.6x crop.
FD
FD stands for Full Diaphragm and means the diaphragm is fully open during focusing and metering. It refers to Canon’s discontinued manual focus lens mount.
FDn lenses are the same as FD lenses but with SSC coatings.
FL stands for reFLex. FL lenses use the same FD mount but can’t meter at full aperture.
IS
IS stands for Image Stabilisation.
L
L stands for Luxury and denotes Canon’s professional range of lenses that usually have a red ring around the end.
MP-E
MP-E stands for Macro Photo EF. There’s only one of these lenses, and it’s designed for extreme magnification. However, there’s no focus ring, and you have to focus by physically moving the lens.
RF
RF stands for Reimagined Focus and denotes Canon’s lens mount for its full-frame mirrorless cameras.
RF-S
RF-S stands for Reimagined Focus-Small. It denotes lenses that have a smaller image circle as they’re designed for use with Canon’s APS-C cameras that have a 1.6x crop.
SC
SC stands for Spectra Coating, which reduces lens reflections and increases contrast.
SSC
SSC stands for Super Spectra Coating, which minimises lens reflections and increases contrast.
STM
STM stands for STepper Motor. This offers quieter, smoother focusing when shooting video or stills.
SWC
SWC stands for Sub-Wavelength Coating, which reduces flare and ghosting and has now replaced SC and SSC coatings.
TS-E
TS-E stands for Tilt Shift Electro and refers to Canon’s range of tilt-shift lenses for EF mounts.
UD
UD stands for Ultra-low Dispersion. This is a type of glass with a low refractive index and low dispersion that improves optical performance.
USM
USM stands for UltraSonic autofocus Motor. This speeds up focus acquisition while allowing manual override, which is ideal for stills.
Nano USM offers fast, smooth and quiet focusing.
Micro USM is a smaller version that doesn’t allow full-time manual override.
Nikon
Here’s a list of all the markings you might find on a Nikon lens.
AF-S
AF-S stands for Auto Focus Silent and denotes a lens with a Silent Wave motor.
D
D stands for Distance and denotes an older type of Nikon lens that didn’t have electronic diaphragm control.
DX
DX is Nikon’s brand name for its crop sensor APS-C cameras and lenses. The DX sensor measures 24 x 16mm. DX lenses are optimised for DX cameras. If there’s no DX on the lens, it means it’s designed to be used with full-frame cameras.
E
E denotes that the lens has electronic aperture activation.
G
G denotes that the lens has electronic diaphragm control.
N
N stands for Nano and shows that the lens has Nikon's Nano Crystal Coat to reduce reflections. It’s an anglicised version of Nikkō, which is itself an abbreviation of the company’s original name, Nippon Kōgaku (or Japan Optics).
NIKKOR
Nikkor is Nikon’s brand name for almost all of its lenses.
VR
VR stands for Vibration Reduction, which is Nikon’s brand name for its image stabilisation system. There may just be an ON/OFF switch, or there may be two or even three settings. The first is for normal usage. The second is for panning when you want to limit vertical movement for horizontal panning (or vice versa). The third is for erratic movement, such as when you’re on a boat or in a moving vehicle.
Sony
Here’s a list of all the markings you might find on a Sony lens.
FE
FE stands for Full-frame E-mount lens.
G
G stands for Gold.
GM
GM stands for Gold Master and denotes a Sony Premium G-Master Series lens.
LE
LE stands for Light Edition.
OSS
OSS stands for Optical Steady-Shot, which is Sony's optical image stabilisation system.
RDSSM
RDSSM stands for Ring Drive SuperSonic Wave Motor. This helps make Sony’s autofocus lenses smooth and silent.
SAL
SAL stands for Sony A-mount Lens. This is the prefix to the product number of all Sony’s A-mount lenses.
SAM
SAM stands for Smooth Autofocus Motor.
SEL
SEL stands for Sony E-mount Lens. This is the prefix to the product number of all Sony’s E-mount lenses.
SMO
SMO stands for Smooth Motion Optics and can be found on specialist video lenses.
SSM
SSM stands for SuperSonic Motor. This uses a ring-type piezoelectric motor to provide quieter, faster, and more precise autofocusing.
STF
STF stands for Smooth Transition Focus. These lenses have special APD (apodisation) lens groups that are thicker toward the edges of the lens to provide smoother bokeh highlights.
T*
T* stands for Transparency and refers to the Carl Zeiss T* coating found in Sony’s ZA lenses.
TC
TC stands for TeleConverter.
XD LM
XD LM stands for eXtreme Dynamic Linear Motor. Lenses with this system have a new contactless electromagnetic drive that makes them very quiet, smooth, fast and powerful.
XA
XA stands for eXtreme Aspherical. XA elements in G Master lenses have a much broader curve, making them more compact.
ZA
ZA stands for Zeiss Alpha and denotes a Carl Zeiss lens.
Verdict
Lens technology is advancing all the time, and manufacturers want to advertise their latest breakthroughs on the lenses themselves. It’s easy to get confused by all the numbers and letters, though, so it’s helpful to know what they all mean!
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