A several-blade diaphragm is configured to retain a smooth, circular-shaped aperture opening even when stopped down by two stops from the wide-open aperture A several-blade diaphragm is configured to retain a smooth, circular-shaped aperture opening even when stopped down by two stops from the wide-open aperture. This produces a smooth-edged bokeh in background highlights.

IF improves optical performance by minimizing illumination loss at the corners of the image field, and helps to suppress other aberrations IF provides practical benefits to photographers including a non-rotating front filter ring that facilitates the positioning of polarizing and graduated filters, and more predictable handling because the lens length does not change during focusing. [...]

Dynamic Rolling-cam mechanism operates the heavy focusing unit of the fast-aperture with high speed and accuracy Thanks to Dynamic Rolling-cam mechanism, which operates the heavy focusing unit with high speed and accuracy, TAMRON has succeeded in minimizing the drive load placed on the focus lens component. This breakthrough ensures stable AF operating performance and improves [...]

Multiple-Cam Zoom Mechanism incorporates several precision cams cut into a single cylindrical surface using high-tech automated machinery Multiple-Cam Zoom Mechanism is an original TAMRON design that incorporates several precision cams cut into a single cylindrical surface using high-tech automated machinery. This key component enables zoom lens barrels to be extended and retracted effortlessly, achieving commendably [...]

Polycarbonate is the material used whenever TAMRON produces high-precision components that require the strength to withstand rigorous use To insure the highest levels of performance and durability without adding additional weight, For example, TAMRON all-in-one zoom lenses make extensive use of engineering plastic (polycarbonate) materials in many critical mechanical components of the lens. Indeed, polycarbonate [...]

Zoom Lock switch prevents undesired extension of the lens barrel when carrying the camera/lens unit on a neck strap Zoom Lock switch prevents undesired extension (creep) of the lens barrel when carrying the camera/lens unit on a neck strap. This enhances responsiveness in the field and helps protect the lens.

This mechanism quickly locks or unlocks the zoom at any position by sliding the zoom ring This mechanism quickly locks or unlocks the zoom at any position simply by sliding the zoom ring. Photographers can shoot from any angle without the zoom extending unintentionally.

Leak-resistant seals throughout the lens barrel help protect your equipment when shooting outdoors For greater protection when shooting outdoors, leak-resistant seals throughout the lens barrel help protect your equipment. ※The structure is moisture-resistant but does not completely prevent the ingress of water droplets.

An internal zoom provides stability by minimizing changes to the center of gravity while shooting An internal zoom provides stability by minimizing changes to the centre of gravity while shooting. Since the total length of the barrel never changes while zooming, you can easily shoot through obstructions such as wire fencing.