Acronyms, terms and nomenclature of SLR camera lenses

Each manufacturer typically uses different terms in the brand name to refer to the characteristics of the lens. From the name we can know for example if it includes an image stabilizer, the type of mount, automatic focus, etc.

Basic terminology for objectives

Focal distance

It is indicated in millimeters. If it is a fixed lens, the corresponding focal length will appear (eg 50mm ) and if it is a zoom lens the range will appear (eg 70-300mm ). What is the focal length?

Aperture range

Usually the maximum aperture of the lens iris is indicated .

If it is a zoom lens, the maximum aperture at the lowest focal length and the maximum aperture at the largest focal point are indicated.

Aperture is indicated by the number f. The smaller the number, the larger the maximum aperture of the diaphragm . Some formats to indicate the lens aperture (the example corresponds to a zoom lens with a maximum aperture of 2.8 at the shortest focal length and a maximum aperture of 3.3 at the longest focal length:

1: 2.8-3.3
F / 2.8-3.3
f / 2.8-3.3


When a lens indicates the word Macro, it means that it allows you to focus on an object at a very short distance (in relation to its focal length).

Strictly speaking, macro lenses are those that can offer a magnification ratio of 1: 1 (or greater) between the size of the object being photographed and the size of the sensor.

It should be noted that some lenses include the Macro option but do not offer a 1: 1 magnification ratio, so from a strict point of view they would not be macro lenses.

Acronyms on Canon lenses

Example: Canon EF-S 55-250mm f / 4-5.6 IS STM

Frame type

The mount type indicates the system or subsystem to which the lens belongs. A system is the set of cameras and lenses compatible with each other.

EF ( Electronic Focus )

It is the mount used in all Canon EOS SLR cameras. EF lenses are compatible with all Canon DSLR cameras, both Full Frame and APS-C sensors.

EF-S ( Short-Back Electronic Focus )

It is the one used in Canon SLR cameras with APS-C sensor. That is, on a Canon EOS with APS-C sensor we can use EF and EF-S lenses, but on a Canon EOS with Full Frame sensor we can only use EF lenses (EF-S lenses will produce vignetting, darkening around the center of the picture).

EF-M ( Mirrorless Electronic Focus )

This mount corresponds to Canon’s M system of mirrorless cameras with APS-C sensor.

The EF-M lenses are good for Canon SLR .

The EF and EF-S itself can be used in cameras M system using an adapter .


This mount corresponds to Canon’s R mirrorless camera system. They are mirrorless cameras with a Full Frame sensor aimed at the professional sector.

The RF goals are not compatible with Canon SLR cameras or the M system .

The EF lenses can be used in other chambers of the system R using an adapter .

Autofocus system

USM ( Ultrasonic Motor )

Ultrasonic wave based system that enables fast and relatively quiet focus movement

STM ( Stepping Motor )

New system for Canon lenses, significantly smoother and quieter than USM lenses

All Canon lenses include an internal autofocus motor. Canon cameras do not have an internal focus motor (in the body).

Specific functions and features

IS ( Image Stabilization )

The lens includes an image stabilization system

IF ( Internal Focus )

Indicates that the focus lens shift is internal, occurs within the lens with no element shift outside the lens (in other words, the lens does not ‘grow’ as the focus changes).

Lens version

When, for example, an improved version of a lens is manufactured, Canon indicates this by Roman numerals (II), with or without the word Mark (Mark II). A higher version usually indicates an improvement in the performance or characteristics of the lens.

L ( luxury )

High-end Canon lenses. They are identified by a red ring at the end of the lens (and are also easily recognized by the price)

Acronyms on Nikon lenses

Nikkor is Nikon’s division in charge of manufacturing lenses. Nikkor, Nikon, or both may appear in the name of a lens.

Example: Nikon AF-S Nikkor 18-35mm f: 3.5-4.5G ED

Lens type / sensor size


They are lenses designed specifically for cameras with APS-C sensor. They can work with Nikon full frame cameras but the camera usually automatically goes into ‘crop mode’ and only uses a sensor area equivalent to an APS-C sensor. That is, the lens itself, due to its geometry, already introduces the crop factor.


These lenses can be used by all Nikon SLR cameras, both with Full Frame sensors and APS-C sensors.

Typically FX lenses are more expensive than their corresponding DX version. And not all FX lenses have a DX version. FX lenses are usually professional, high-end lenses. In DX format it is not usual to find professional objectives.

Focus System

AF ( Auto Focus )

The lens allows automatic focus (autofocus – AF) but does not include an internal focus motor. It is the camera that has to incorporate a focus motor in the body. For example, the cameras of the D3000 (D3200, D3300…) and D5000 (D5200, D5300, D5500…) series do not include a focus motor in the body and therefore could not use the autofocus system with these lenses, they would have to be used with manual focus.

AF-S ( Auto Focus Silent )

Quieter autofocus system. The technology it uses is SWM (Silent Wave Motor) which would correspond to Canon’s USM (Ultrasonic Motor). These lenses include the focus motor and the camera does not need to have a focus motor in the body. AF-S lenses are compatible with all Nikon SLR cameras.

AF-P ( Auto Focus Pulse Motor )

Stepper type internal focus motor lenses. This type of system is specially designed for video as it offers smoother movement between focus areas within the scene.

IMPORTANT: AF-P lenses are not compatible with all Nikon SLR cameras. They are compatible with the models of each series starting from the D3300, D5500, D7500.

Specific functions and features

VRVibration Reduction )

The lens includes an image stabilization system


They do not have a ring to control the opening manually. That is, the aperture is controlled by the camera and there is no possibility to change it manually from the lens.

IF ( Internal Focus )

Indicates that the focus lens shift is internal, occurs within the lens without any shift of elements outside the lens.


Different technologies to correct or minimize chromatic aberrations.

LD (Low Dispersion), ED (Extra low dispersion) and UD (Ultra low dispersion). In other words, a UD lens will have higher optical quality in terms of color aberration than an ED or LD lens.


Nanocrystal coated lenses. This technology eliminates or minimizes flares and generally offers sharper and more contrasting images.

Acronyms on Pentax lenses

Example: Pentax HD DA 55-300mm F4-5.8 ED WR

Target type


Specific lenses for cameras with APS-C sensor


Lighter version, with a plastic frame instead of metal. They are usually cheaper than their corresponding DA versions


The asterisk (star) indicates the high end of Pentax lenses for its APS-C cameras. They are of higher optical quality and almost all models in this range are sealed (they prevent the entry of water, dust, etc.)

All these lenses are compatible with all Pentax SLR camera models, the only difference is the quality.


Lenses for Pentax cameras with Full Frame sensor (for example Pentax K-1 / K-1 mark II)

These lenses are compatible with APS-C sensor cameras.

Focus System

Pentax DSLR cameras include an in-body focus motor, therefore all DA, DAL and DA * lenses allow autofocus


Lenses with the acronym DC or SDM (Supersonic Drive Motor) incorporate their own focus motor

Specific functions and features

WR (Weather Resistant)

They are sealed lenses that keep out water and dust

AW (All Weather)

They are also sealed targets, assumed to have a higher degree of construction and tightness than WR.

SMC | SMCP (Super Multi Coating process)

Lenses in which specially coated lenses are used to improve optical parameters, avoid internal reflections, light scattering, flares, etc. Many of the Pentax lenses are SMC


Optical elements with very low dispersion (Extra low Dispersion)


An indicator similar to * that identifies high-quality Pentax lenses

IF(Internal Focus)

Indicates that the focus lens shift is internal, occurs within the lens without any shift of elements outside the lens.

Acronyms on Tamron lenses

Tamron manufactures lenses for major brands of SLR cameras

Example: Tamron A14P AF 18-200mm F / 3.5-6.3 XR Di II LD ASL (IF)

Target type

Di(Digitally Integrated)

Lenses for use with both Full-frame and APS-C sensor reflex cameras

Di-II(Digitally Integrated II)

Specific lenses for cameras with APS-C sensor

Di-III(Digitally Integrated III)

Lenses specifically designed for mirrorless cameras (eg mirrorless cameras from Sony, Olympus, Panasonic)


Listed next to model number: E (Canon EF mount), N or NII (Nikon mount), P (Pentax), S (Sony)

For example, for a Tamron 18-200mm lens

Tamron A14 E – for Canon
Tamron A14 NII – for Nikon
Tamron A14 P – for Pentax
Tamron A14 S – for Sony

Focus System

AF(Auto focus)

Includes autofocus function

USD(Ultrasonic Silent Drive)

Lenses with integrated focus motor

PZD(Piezo Drive)

Lenses with a built-in piezoelectric focus motor. Faster and quieter

Specific functions and features

VC(Vibration Compensation)

The lens includes an image stabilizer. Tamron often makes very efficient image stabilization systems.


The objective includes low dispersion lenses (Low dispersion | Extra low dispersion)


The objective includes aspherical lenses, which avoid or minimize the optical aberrations associated with spherical lenses


Objective with aspherical lenses and low dispersion

AD(Anomalous Dispersion)

Lenses with elements that avoid or minimize chromatic aberration


Objective with aspherical lenses and enhancement of chromatic aberration

IF(Internal Focus)

Indicates that the focus lens shift is internal, occurs within the lens without any shift of elements outside the lens.

SP(Super Performance)

Professional line. High-quality lenses