Tamron 70-300mm f/4.5-6.3 Di III RXD vs Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD

Both are Sony E mount zooms for telephoto and travel — 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 70-300mm f/4.5-6.3 Di III RXD	Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD
Focal length	70-300mm	18-300mm
Max aperture	f/4.5-6.3	f/3.5-6.3
Type	zoom	zoom
Coverage	full-frame	APS-C
Mount	Sony E	Sony E

Which should you buy?

the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD opens wider (f/3.5-6.3) — brighter in low light and more background blur
the Tamron 70-300mm f/4.5-6.3 Di III RXD covers 70-300mm and the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD covers 18-300mm — pick the range that matches what you shoot
the Tamron 70-300mm f/4.5-6.3 Di III RXD covers full-frame (also works on APS-C bodies); the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD is APS-C-only — it won't fill a full-frame sensor

Where to buy

Tamron A047SF - Telephoto Lens - 70-300mm F/4.5-6.3 Di III RXD for Sony FE, Black

Tamron 70-300mm f/4.5-6.3 Di III RXDSee price on Amazon

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Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD Lens for Sony E APS-C Mirrorless Cameras (Black)

Tamron 18-300mm f/3.5-6.3 Di III-A VC VXDSee price on Amazon

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FAQ

What's the difference between the Tamron 70-300mm f/4.5-6.3 Di III RXD and the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD?
The Tamron 70-300mm f/4.5-6.3 Di III RXD is 70-300mm f/4.5-6.3 zoom, full-frame; the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD is 18-300mm f/3.5-6.3 zoom, APS-C. Both fit the Sony E mount.

Which is better in low light, the Tamron 70-300mm f/4.5-6.3 Di III RXD or the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD?
The Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD — its f/3.5-6.3 maximum aperture lets in more light and gives more background blur than the f/4.5-6.3 of the other.

Do the Tamron 70-300mm f/4.5-6.3 Di III RXD and Tamron 18-300mm f/3.5-6.3 Di III-A VC 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). Note the Tamron 18-300mm f/3.5-6.3 Di III-A VC VXD 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 70-300mm f/4.5-6.3 Di III RXDAffiliate linkSee price on Amazon