FitMyLensthe lens-by-mount reference

Sony FE 20-70mm f/4 G vs Tamron 20-40mm f/2.8 Di III VXD

Both are Sony E mount zooms for everyday and travel — here's how the specs differ and which to pick. Every spec is from the manufacturer's own catalog.

Last verified 2026-06-21 · Sony E mount · prices change — check the retailer

SpecSony FE 20-70mm f/4 GTamron 20-40mm f/2.8 Di III VXD
Focal length20-70mm20-40mm
Max aperturef/4f/2.8
Typezoomzoom
Coveragefull-framefull-frame
MountSony ESony E

Which should you buy?

Where to buy

Check the Sony FE 20-70mm f/4 G price on Amazon →

Check the Tamron 20-40mm f/2.8 Di III VXD price on Amazon →

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FAQ

What's the difference between the Sony FE 20-70mm f/4 G and the Tamron 20-40mm f/2.8 Di III VXD?
The Sony FE 20-70mm f/4 G is 20-70mm f/4 zoom, full-frame; the Tamron 20-40mm f/2.8 Di III VXD is 20-40mm f/2.8 zoom, full-frame. Both fit the Sony E mount.

Which is better in low light, the Sony FE 20-70mm f/4 G or the Tamron 20-40mm f/2.8 Di III VXD?
The Tamron 20-40mm f/2.8 Di III VXD — its f/2.8 maximum aperture lets in more light and gives more background blur than the f/4 of the other.

Do the Sony FE 20-70mm f/4 G and Tamron 20-40mm f/2.8 Di III VXD fit the same camera?
Yes — both are Sony E mount lenses, so they fit Sony a7/a9/a1 (full-frame) and a6000-series (APS-C).

More Sony E comparisons: Sony FE 50mm f/1.4 GM vs Sigma 50mm f/1.4 DG DN Art · Sony FE 40mm f/2.5 G vs Sony FE 50mm f/2.5 G · Sony E 15mm f/1.4 G vs Sigma 16mm f/1.4 DC DN Contemporary · Sony FE 24mm f/1.4 GM vs Sigma 24mm f/1.4 DG DN Art · all Sony E lenses · all comparisons