Tamron 17–70mm F2.8 Di III-A VC RXD vs Sigma 50-120mm f/2.8 DC OS Contemporary

Both are Fujifilm X zoom lenses for APS-C. Here is what actually differs.

Tamron · 2022

17–70mm F2.8 Di III-A VC RXD

f/2.8RXD

Full specs

Sigma · 2026

50-120mm f/2.8 DC OS Contemporary

f/2.8390 gLinear motor

Full specs

Pick the Tamron 17–70mm F2.8 Di III-A VC RXD if

You want a wider view: 17mm vs 50mm at the wide end
You shoot close-ups: it focuses down to 0.19 m vs 0.23 m

Pick the Sigma 50-120mm f/2.8 DC OS Contemporary if

You need more reach: 120mm vs 70mm at the long end
You want bigger close-ups: 0.33× vs 0.21× maximum magnification
You care about the shape of out-of-focus highlights: 11 aperture blades vs 9
You prefer a newer design: released 2026 vs 2022

Spec differences

12 differences

Specifications that differ between the Tamron 17–70mm F2.8 Di III-A VC RXD and the Sigma 50-120mm f/2.8 DC OS Contemporary
	Tamron 17–70mm F2.8 Di III-A VC RXD	Sigma 50-120mm f/2.8 DC OS Contemporary
Brand	Tamron	Sigma
Focal length	17-70mm	50-120mm
Weight	not listed	390 g
Length	not listed	99.3 mm
Diameter	74.6 mm	66.8 mm slimmer
Filter thread	67 mm	55 mm
Min focus distance	0.19 m closer	0.23 m
Max magnification	0.21×	0.33× larger
Aperture blades	9	11 more blades
Optical design	16 elements / 12 groups	18 elements / 13 groups
Autofocus motor	RXD	Linear motor
Released	2022	2026

6 identical specs hidden: mount, type, format, max aperture, image stabilization, weather sealing. Show all

Mount: Fujifilm X both
Type: Zoom both
Format: APS-C both
Max aperture: f/2.8 both
Image stabilization: Yes both
Weather sealing: Yes both

Our notes

Tamron 17–70mm F2.8 Di III-A VC RXD

This 17-70mm f/2.8 APS-C fast standard zoom lens from Tamron fits Fujifilm X mount cameras, with Vibration Compensation and quiet motor-driven autofocus. The range covers everything from wide scenes to portraits, so it works as a general-purpose lens.

Our notes