Tamron 20mm f/2.8 Di III OSD M1:2 vs 7Artisans AF 18mm f/2 (APS-C)

Both are Sony E mount primes for wide-angle and street — here's how the specs differ and which to pick. Every spec is from the manufacturer's own catalog.

Last verified 2026-09-01 · Sony E mount · prices change — check the retailer

Spec	Tamron 20mm f/2.8 Di III OSD M1:2	7Artisans AF 18mm f/2 (APS-C)
Focal length	20mm	18mm
Max aperture	f/2.8	f/2
Type	prime	prime
Coverage	full-frame	APS-C
Mount	Sony E	Sony E

Which should you buy?

the 7Artisans AF 18mm f/2 (APS-C) opens wider (f/2) — brighter in low light and more background blur
the 7Artisans AF 18mm f/2 (APS-C) (18mm) is wider — more in the frame for street and interiors; the Tamron 20mm f/2.8 Di III OSD M1:2 (20mm) is tighter — more reach and compression for portraits
the Tamron 20mm f/2.8 Di III OSD M1:2 covers full-frame (also works on APS-C bodies); the 7Artisans AF 18mm f/2 (APS-C) is APS-C-only — it won't fill a full-frame sensor

Where to buy

Tamron 20mm f/2.8 Di III OSD M1:2 Lens for Sony Full Frame/APS-C E-Mount | 20mm f/2.8 lens with 1:2 magnification and OS

Tamron 20mm f/2.8 Di III OSD M1:2See price on Amazon

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7artisans AF 18mm F2.0 Auto Focus APS-C Wide Angle Lens for Sony E Mount | Ultra Lightweight 109g,STM,Type-C Upgrade for

7Artisans AF 18mm f/2 (APS-C)See price on Amazon

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FAQ

What's the difference between the Tamron 20mm f/2.8 Di III OSD M1:2 and the 7Artisans AF 18mm f/2 (APS-C)?
The Tamron 20mm f/2.8 Di III OSD M1:2 is 20mm f/2.8 prime, full-frame; the 7Artisans AF 18mm f/2 (APS-C) is 18mm f/2 prime, APS-C. Both fit the Sony E mount.

Which is better in low light, the Tamron 20mm f/2.8 Di III OSD M1:2 or the 7Artisans AF 18mm f/2 (APS-C)?
The 7Artisans AF 18mm f/2 (APS-C) — its f/2 maximum aperture lets in more light and gives more background blur than the f/2.8 of the other.

Do the Tamron 20mm f/2.8 Di III OSD M1:2 and 7Artisans AF 18mm f/2 (APS-C) 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 7Artisans AF 18mm f/2 (APS-C) is APS-C-only and won't fill a full-frame sensor.

Citing these specs? Go ahead — manufacturer data, last verified 2026-09-01. Copy a ready-made reference:

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Tamron 20mm f/2.8 Di III OSD M1:2Affiliate linkSee price on Amazon