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Tamron 13VM20100AS 20-100mm F1.6 Vari-Focal Lens — main product image
Tamron

Tamron 13VM20100AS 20-100mm F1.6 Vari-Focal Lens

A 20-100mm F1.6 zoom built for 1/3" sensors — versatile focal range and a fast aperture that keeps your subject sharp from wide to telephoto.

$176.10*
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*Price sourced from Amazon.com. Last updated:Jul 14, 2026.Price and availability are subject to change.

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Overview

The Tamron 13VM20100AS is a 20-100mm F1.6 aspherical vari-focal lens designed for cameras using 1/3" image sensors — a format found in industrial imaging, machine vision systems, and compact professional video applications. The 20-100mm zoom range gives users a wide compositional spread on a single optic, covering the equivalent of a wide establishing shot through a tight telephoto on this sensor format. The F1.6 maximum aperture is notably fast for a zoom lens, enabling usable exposures in lower light conditions and providing the depth-of-field control that faster glass delivers even at the longer end of the focal range. The aspherical element design addresses spherical aberration — the optical flaw that causes blurring toward frame edges when shooting wide open — and contributes to sharpness that holds across the zoom range rather than peaking only at mid-aperture.

This is a manual iris lens, meaning aperture is set mechanically rather than electronically. That's a deliberate fit for controlled installations and studio environments where lighting is consistent and exposure is dialed in once per session. The vari-focal design — where focus shifts when the focal length changes — is standard for this lens class and requires a refocus step after each zoom adjustment. Build quality is appropriate for the specialty imaging market this lens serves, and the optical corrections are engineered specifically for the 1/3" image circle rather than adapted from a larger-format design. If your camera platform uses 1/3" sensors and your workflow benefits from a wide-to-telephoto zoom at a fast maximum aperture, the 13VM20100AS covers that range with the optical quality Tamron's aspherical designs are known for.

Key Features

Tamron Aspherical Manual Iris Zoom Lens 13VM20100AS

Specifications

Focal Length
20-100mm
Maximum Aperture
F/1.6
Lens Type
Vari-Focal Zoom
Iris Type
Manual
Lens Design
Aspherical
Sensor Compatibility
1/3" Format
Model
13VM20100AS

Pros & Cons

👍 Pros

  • The 20-100mm focal range delivers wide-to-telephoto versatility on a single lens — covering broad context shots and tight isolations without a lens swap.
  • F1.6 maximum aperture is fast for a zoom, pulling in more light at the telephoto end where slower zooms force compromises in low-light or indoor conditions.
  • Aspherical lens construction corrects spherical aberration across the zoom range, maintaining edge sharpness and reducing the aberration that soft-looking variable zoom lenses often exhibit wide open.
  • Manual iris gives precise, repeatable aperture control in controlled shooting environments where consistent exposure is more important than automatic reactivity.
  • Designed specifically for 1/3" sensors, the image circle and optical corrections are matched to the format rather than adapted from a larger-sensor design.

👎 Cons

  • As a vari-focal rather than parfocal lens, focus must be re-established after each focal length change — this adds a step to any workflow that involves regular zooming during a session.
  • Manual iris only — there is no automatic aperture control, which limits usability in run-and-gun or rapidly changing light situations where you need responsive exposure adjustment.
  • Designed for 1/3" sensors, this lens is not compatible with APS-C, Micro Four Thirds, or full-frame interchangeable lens camera systems — it's a specialty optic for a specific format.
  • Feature information from the manufacturer is minimal, so confirming exact mount compatibility and image circle coverage requires careful cross-referencing with your specific camera model.

Frequently Asked Questions

This lens is designed for cameras with 1/3" image sensors — the format common in industrial, machine vision, and compact video applications. Confirm the mount type matches your specific camera body before purchasing, as this is a specialty lens not designed for consumer interchangeable-lens camera systems.
With a manual iris you set the aperture by hand — there's no auto-exposure through the lens. This is standard in controlled environments like studio setups or fixed installations where exposure is set once, but it requires manual adjustment if ambient light changes significantly during a shoot.
Aspherical elements correct for spherical aberration — the optical distortion that causes blur at the edges of the frame — which is especially valuable at wide apertures like F1.6. The result is sharper edges and better corner-to-corner consistency than comparable all-spherical designs.
The 1/3" sensor format has a significant crop factor compared to full-frame. The 20-100mm range on a 1/3" sensor covers a wide-to-telephoto spread that provides considerable compositional flexibility — from broader environmental context at 20mm to tight subject isolation at 100mm.
Yes — vari-focal lenses typically require refocusing when the focal length is changed, unlike parfocal zoom lenses which hold focus through the zoom range. This is a standard characteristic of vari-focal design and is worth accounting for in your workflow.

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