FitMyLensthe lens-by-mount reference

Tamron 20-40mm f/2.8 Di III VXD vs Sigma 18-50mm f/2.8 DC DN Contemporary

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

SpecTamron 20-40mm f/2.8 Di III VXDSigma 18-50mm f/2.8 DC DN Contemporary
Focal length20-40mm18-50mm
Max aperturef/2.8f/2.8
Typezoomzoom
Coveragefull-frameAPS-C
MountSony ESony E

Which should you buy?

Where to buy

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

Check the Sigma 18-50mm f/2.8 DC DN Contemporary price on Amazon →

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FAQ

What's the difference between the Tamron 20-40mm f/2.8 Di III VXD and the Sigma 18-50mm f/2.8 DC DN Contemporary?
The Tamron 20-40mm f/2.8 Di III VXD is 20-40mm f/2.8 zoom, full-frame; the Sigma 18-50mm f/2.8 DC DN Contemporary is 18-50mm f/2.8 zoom, APS-C. Both fit the Sony E mount.

Do the Tamron 20-40mm f/2.8 Di III VXD and Sigma 18-50mm f/2.8 DC DN Contemporary 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). Note the Sigma 18-50mm f/2.8 DC DN Contemporary is APS-C-only and won't fill a full-frame sensor.

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 20-70mm f/4 G vs Tamron 20-40mm f/2.8 Di III VXD · all Sony E lenses · all comparisons