The lens at BHphoto. Adorama. Amazon US&EU. FotoKoch.
SonyAlphaBlog tested the Tamron 20-40mm FE lens and concluded:
The Tamron 20-40mm F2.8 Di III VXD (999 euros) , is proposing a usual zoom range that will suit vlogger , and photographer who mix street and architecture/landcsape and a tiny bit of portraits. It will also be an ideal complement to a Tamron 35-150mm F2-2.8 Di III VXD
Its performances are very good overall with very good sharpness especially at 20mm but nothing excellent neither specially in the corners that are a little bit weak at 40mm wide open. For best results across the frame you will need to close down to F5.6 . Bokeh is very good, as well as color rendering and smoothness of background blur
The images are automatically corrected in Lightroom for distortion and vignetting. Resistance flare is a bit average
In term of competition there is no direct equivalent the best replacement are either
- The Sony PZ 16-35mm F4 G deliver superior performance (sharpness, ergonomics) with a wider focal range but do not have the F2.8 aperture
- The Duo Tamron 20mm F2.8 (300 euros) + Tamron 35mm F2.8 (300 euros), that offer superior sharpness
- The Duo Sony 24mm F2.8 G (600 euros) + Sony 40mm F2.5 G (600 euros) that offers superior sharpness, ergonomics color rendering and AF speed but less versatility
The Tamron 20-40 will be ideal only if you really need the variability of a zoom , a F2.8 and this specific focal range and will be more at ease on a A7IV (33Mpix) than on a A7RV (61Mpix)