Lens jargon – Lens names explained

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If you own an interchangeable lens camera and are looking at purchasing a new lens, you may wonder what all those different numbers and letters that form part of the lens name mean. Or you may just be wondering what they mean on your current lens / camera.

Lens jargon - Lens names and nomenclature explained

The numbers and letters are included as part of the lens name by manufacturers to give brief information about the lens. Unfortunately, different manufacturers tend to use different nomenclature, which makes comparing lenses difficult.

So, in the end it can often seem like they are included more for marketing purposes than anything else. A lens with a lot of different acronyms after it's name might sound better in the same way that people sometimes list their qualifications or organizations they are certified by after their names.

First, let's look at an example of a lens name:

Canon EF 24-70mm f/2.8L II USM

Now, let's break that down.

Canon

Is the lens manufacturer's name. In some cases third party manufacturers produce lenses under several different brand names, for example, Samyang, Walimex, Bower, and Rokinon are all names used for branding lenses produced by Samyang.

EF

Is the lens mount of the lens. For this example, it means that the lens will only work with cameras that have an EF compatible lens mount. You can read more about lens mounts in this article: Lens mounts and interchangeable lenses.

24-70mm

Is the focal length or focal length range of the lens.

f/2.8

Is the maximum aperture value of the lens. (The smaller the number, the more light the lens can let in, and the greater the control you have over the amount of the image that is in focus).

In the case of zoom lenses with a variable maximum aperture, this will be expressed as a range, such as f/3.5-5.6. The left value means the maximum aperture when the lens is set at it's widest focal length, the right value is the maximum aperture when the lens is zoomed in.

Sometimes the aperture may be expressed as a ratio, for example 1:2.8 instead of f/2.8.

L

Is a designation used by Canon to denote this lens is part of their high end 'Luxury' series.

II

Indicates this is the second version of this lens model. When a manufacturer improves a lens design, but doesn't add any additional features, then they will add a version number to distinguish from the previous version of the lens.

Note that manufacturers may sometimes make small improvements to a lens, and release it without changing the version number. In this case the only way to differentiate a newer model from an older one is using date codes or serial numbers printed on the lens.

USM

Means that the lens contains an ultrasonic motor (used for autofocus). This is a Canon specific designation, we'll look at other manufacturers in a minute.

So far we just looked at a single lens from a single manufacturer. There are lots of different lenses produced by different manufacturers, and they use different acronyms to mean the same or similar thing. I'll try and make sense of these in a way that should hopefully make comparing lenses across manufacturers easier below. For most of the acronyms I've linked them to where you can read more information about what they mean.

Just Kit Lens
Just Kit Lens by Lambroso on flickr (licensed CC-BY-SA)

Macro

A lens labeled with macro means it can focus closely for good enlargements of small subjects. It does not necessarily mean that the lens is capable of true macro, some lenses may be capable of greater enlargements than others. You will need to check the maximum reproduction ratio for the lens to see just how macro the lens really is. You can read more on true macro and reproduction ratios here: What is macro photography?

NotationUsed by
MacroCanon, Sigma, Pentax, Olympus, Panasonic
MicroNikon
MakroZeiss
MSony

Focusing

Generally lens names contain an acronym that relates to the type of focusing motor used in the lens. Nikon produces cameras with and without built-in focusing motors. If you have camera that does not have a built-in focusing motor, then you must make sure that any lens you buy does contain a focusing motor, otherwise the lens won't be able to be autofocused. (But manual focus will still work).

You can't really tell the focusing performance of a lens just from the type of focus motor used. So this information isn't that useful. To check performance you are best off reading reviews of the particular lens you are interested in.

NotationUsed byMeaning
USMCanonUltrasonic Motor (fast and quiet)
STMCanonStepping Motor (works well for contrast detect autofocus)
AF-SNikonSilent Wave Motor (fast and quiet)
AF-INikonInternal Motor
AFNikon, Pentax, TokinaAutofocus lens, no motor (requires body with motor for autofocusing). (Tokina lenses for Canon cameras do have a motor though).
SWDOlympusSupersonic Wave Drive motor (fast and quiet)
SDMPentaxSupersonic Drive Motor (fast and quiet)
SSMSonySupersonic Motor (fast and quiet)
SAMSonyMicro motor
USDTamronUltrasonic Silent Drive motor (fast and quiet)
PZDTamronPiezoelectric drive motor
HSMSigmaHypersonic Motor (fast and quiet)
IFAllInternal Focusing (Lens doesn't change length when it is focused)

Glass

There are an incredible number of different notations used by lens manufacturers to denote the optical properties of glass and coatings used in their lenses. As with focusing, I wouldn't pay much attention to these when judging a lens.

The effectiveness of the coatings and glass used in best judged by reading a review of the lens and looking at photos taken with that lens in situations similar to how you would use it.

NotationUsed byMeaning
DOCanonDiffractive Optics
NNikonNano-Crystal Coating
SICNikonSuper Integrated Coating
EDNikon, PentaxLens contains one or more Extra-low Dispersion elements
FLNikonLens contains one or more fluorite elements. Canon also uses fluorite in some of their lenses, but does not use a designation to advertise this. Mostly it is only used in high end super telephoto lenses.
ALPentaxLens contains one or more Aspherical elements
SMCPentaxSuper Multi Coating
HDPentaxHigh Definition Coating
APOSony, SigmaApochromatic correction - note that these do not tend to be true APO lenses. Lenses with true Apochromatic correction are very expensive.
T*Sony, ZeissHigh-performance Coating.
ADTamronLens contains one or more Anomalous Dispersion elements.
ASLTamronLens contains one or more Aspherical elements.
XRTamronLens contains one or more Extra Refractive elements (lighter, smaller lenses).
LDTamronLens contains one or more Low Dispersion elements.
XLDTamronLens contains one or more Extra Low Dispersion elements.
HIDTamronLens contains one or more High Index, High Dispersion elements.
ASPSigmaLens contains one or more Aspherical elements

Image stabilization

An image stabilization system may be built into the lens. This helps you shoot at lower shutter speeds without blurring from camera shake.

Name area on an AF-S VR Zoom-Nikkor 70-300mm f/4.5 - 5.6G IF-ED lens

Some manufacturers build image stabilization into their camera bodies. In this case a lens with stabilization doesn't offer any benefit, since any lens used with the camera will be stabilized.

NotationUsed byMeaning
ISCanonImage Stabilization
VRNikonVibration Reduction
OSSSonyOptical Steady Shot
OSSigmaOptical Stabilizer
VCSonyVibration Compensation
OISPanasonicOptical Image Stabilization

Image circle size

Interchangeable lens cameras are produced with a variety of different image sensor sizes. The main issue is with DSLR / SLT cameras, where you can purchase cameras with APS-C and 35mm full frame size sensors. (See What is Crop Factor? for more information).

A lens designed for use with a smaller APS-C size sensor will not work properly on a camera with a 35mm full frame size sensor. The edges of the frame will likely be solid black, and the image will exhibit very bad vignetting. So, lenses are often marked to designate if they are only designed for cameras with APS-C size sensors.

NotationUsed by
EF-SCanon
DXNikon
DTSony / Konica Minolta
DAPentax
Di IITamron
DC, DNSigma
DXTokina

Build

Some manufacturers also label their lenses to indicate a certain level of build quality.

NotationUsed byMeaning
LCanonLuxury (high performance and construction)
WR / AWPentaxWeather Resistant / All Weather
*PentaxHigh performance and weather sealed
LimitedPentaxHigh performance and compact size
XSPentaxExtra Slim, small size
GSonyGold (high performance and construction)
EXSigmaExcellent (high performance and construction)
SPTamronSuper Performance (high performance and construction)

There are other acronyms you may see used as part of a lens name or description as well, but the above are the main ones. The only bits you really need to pay attention to are:

  • The mount - will it fit on your camera?
  • The focal length - will it cover the view you are looking for?
  • The maximum aperture - is it bright enough and will it allow for the amount of background blur you want?
  • The image circle the lens covers - is it suitable for use on your camera?

The other things, such as image quality, focusing speed etc. you can only tell by using a lens or reading a review. If a lens can produce good quality images, it doesn't really matter whether it does that by including super extra low dispersion glass or not.

Written by Discover Digital Photography

July 4th, 2013 at 8:45 am

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