A-Mount: Sony’s proprietary mounting system, acquired from Minolta, used with SLR cameras.
Aspherical Element: Used to correct the alignment of light on the image plane to maintain sharpness and contrast throughout the entire aperture range of the lens.
Advanced Aspherical (AA) Element: An aspherical element characterized by a high thickness ratio between the center and periphery of the element, resulting in improved imaging.
Extreme Aspherical (XA) Element: An aspherical design created by Sony with added surface precision, resulting in improved bokeh.
Apodization (APD): Elements that gradually reduce light transmission toward their periphery, resulting in softened out-of-focus areas.
Bokeh: Describes the out-of-focus areas in an image.
Circular Aperture: A perfect or nearly perfect circular diaphragm design used by Sony to improve defocusing when shooting at smaller apertures.
Direct Drive Super Sonic Wave Motor (DDSSM): A lens motor designed to focus full-frame lenses precisely, quickly, and quietly.
DT: Short for Digital Technology, used to denote Sony lenses designed for cameras with APS-C sensors.
Dust- and Moisture-Resistant Design: An attribute of lenses sealed to protect against light rain, dirt, and other contaminants. Note: this is not the same as being water- and dust-proof.
E-Mount: Sony’s proprietary mounting system used with full-frame and APS-C mirrorless cameras.
Extra-Low Dispersion (ED) Glass: Specialized type of glass used to reduce chromatic aberrations.
Super ED Glass: Provides enhanced protection against chromatic aberration.
Extreme Dynamic Linear Motor (XD LM): A contactless, electromagnetic focusing motor with high thrust for fast, silent autofocusing.
FE: Short for Full-frame E-Mount, used to denote Sony E-mount lenses designed for mirrorless cameras with full-frame sensors.
Floating Elements: Specialized design and mechanism used to maintain sharp focusing at all focusing distances.
Fluorine (F) Coating: A protective coating used on external glass surfaces that increases the contact angle of the lens to liquids, repelling water and oil-based contaminants.
Fluorite Element (FL): A lightweight element that reduces chromatic aberration.
Focus Hold Button (FHB): A button on the side of the lens barrel used to lock focus on a subject. This button can be customized.
Focus Range Limiter (FRL): A switch on telephoto and macro lenses used to restrict focusing to specified distances. This eliminates the chance of autofocus being affected by out-of-range objects while also reducing the amount of time that it takes to hit focus. In some models, you can customize distances for this feature.
G Lens: Originally referred to as Gold lenses, these are Sony’s mid-to-high range lenses.
GM Lens: Also referred to as G Master lenses, these are Sony’s highest-quality lenses.
Internal Focusing (IF): A lens design wherein only the middle or rear groups move to focus, resulting in lenses with shorter minimum focusing distances, faster autofocus, unchanging lengths, and non-rotating filter threads.
Internal Zoom: A means of zooming in which the lens barrel remains the same length and does not rotate. This design feature leaves polarizers and other rotating filters unaffected when the lens is zooming.
Iris/Aperture Ring: A ring on the lens barrel used to select aperture settings manually.
Iris/Aperture Click Switch: Allows lenses to be “de-clicked” for smooth and silent aperture adjustments; particularly beneficial when recording video.
Linear Motor (LM): Used to achieve focus via a contactless electromagnetic drive.
Linear Response Manual Focus (LR MF): Manual focusing achieved using the focusing ring of lenses with linear motors.
Multi-Layered Coating: A thin, anti-reflective coating added to lenses to reduce reflections that cause flare or ghosting.
Nano AR Coating: Sony lens-coating technology, which incorporates a regular nanostructure that transmits light while reducing the reflections that can result in flare or ghosting in images.
Nano AR Coating II: Sony lens-coating technology that incorporates a nanostructure design for use on large or highly curved elements to reduce internal reflections, flare, and ghosting.
Optical SteadyShot (OSS): Sony’s proprietary lens-based image stabilization system, which helps to minimize the effects of camera shake when shooting handheld.
Power Zoom (PZ): A feature that adapts Sony’s camcorder technology for camera lenses, permitting smooth, steady zoom via an in-lens motor without rotating or changing the length of the lens.
Ring Drive Super Sonic Wave Motor (RDSSM): This design features a piezoelectric motor that produces high torque at slow rotation for fast, silent autofocusing.
SAL: Naming convention for Sony A-Mount Lenses.
SEL: Naming convention for Sony E-Mount Lenses.
Smooth Autofocus Motor (SAM): A focusing motor incorporated into the design of the lens for focusing.
Smooth Motion Optics (SMO): Lenses that incorporate video-friendly features, including internal focus, tracking adjustment, and internal zoom.
Smooth Transition Focus (STF): Sony’s designation for lenses with apodization elements.
Stepping Motor (STM): Stepping motors focus by breaking movements down into steps based on electrical impulses.
SuperSonic Motor (SSM): A ring-type ultrasonic focusing motor characterized by fast and quiet focusing.
TC: Sony naming convention for teleconverters.
ZEISS T* Coating: ZEISS proprietary coating applied to multi-element lenses to reduce reflections, minimize flare, and boost contrast.
Zoom Rotation Direction Select Locking Switch: This lens addition allows you to change the direction used to zoom in or out.