Tamron 20-40mm f/2.8 DI III VXD lens

Versatile standard zoom ranges from ultra-wide angle to normal focal length. That’s how well it performs in practice and in the testing laboratory.

With the Tamron 20-40mm f/2.8 Di III VXD lens, the manufacturer expands its currently 16-lens lineup for mirrorless system cameras. Like all standard zooms, it has the advantage of covering a large focal range. This allows photographers to avoid having to constantly change lenses and react more quickly to different situations. It can be used in many ways, from the ultra-wide angle of 20mm, for example for landscape photos, to the standard angle of 40mm, for example for portraits. Testing shows image quality at 20mm, 28mm and 40mm using the fixed aperture of F2.8.

Tamron 20-40mm: High detail resolution

The Tamron 20-40mm f/2.8 Di III VXD features 14 elements in 11 groups, including three aspherical lenses and two LD (low dispersion) elements. The G2 BBAR (broad-band anti-reflective) coating reduces the appearance of lens flares and ghosting, which was noticeable in practice. In the test lab, the optics achieved a very high level of detail resolution, especially in the center of the image, with a moderate decline towards the edge of the image. Resolution is particularly uniform across the entire image with a standard focal length of 40mm and aperture of F5.6.

Shading is not optimal

Vignetting brings the tone down a bit and is particularly loud at 20mm F2.8 with an EV of 1.4. In contrast, lateral chromatic aberration remains well corrected; It remains at about half a pixel across all focal lengths, and distortion is completely eliminated. However, this is associated with a loss of image clarity at the edges. Tamron’s latest VXD (Voice Coil Maximum Torque Drive) autofocus system ensures smooth, accurate focusing, extremely quiet operation, and virtually no noise in practical testing. The large, bright aperture with constant F2.8 not only provides a nice effect, but is also useful in situations with low ambient light. This means you can also take photos at dusk without too long exposures (see example photo above right). Weighing just 370g, the plastic casing is light and airtight against dust and water splashes.

Conclusion

The Tamron 20-40mm f/2.8 Di III VXD has very high, highly uniform detail resolution. Visible vignetting affects the tone and cannot be effectively eliminated by the Alpha 7R III’s camera correction. Adjustment via the app, an ultra-short maximum length of just 17cm, and low weight are attractive bonuses. Anyone who likes to move between ultra-wide angle and standard focal length and is looking for an all-in-one solution will find what they are looking for here.

• for every
  • Very high detail resolution, low weight.

• cons
  • Pronounced shading.