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Sigma 17-40mm f/1.8 DC vs 18-50mm f/2.8 DC DN Contemporary

Both are Leica L zoom lenses for APS-C. Here is what actually differs.

Pick the 17-40mm f/1.8 DC if

  • You need 1⅓ stops more light for low light or background blur (f/1.8 vs f/2.8)
  • You want a wider view: 17mm vs 18mm at the wide end
  • You care about the shape of out-of-focus highlights: 11 aperture blades vs 7
  • You prefer a newer design: released 2025 vs 2021

Pick the 18-50mm f/2.8 DC DN Contemporary if

  • You want the lighter lens to carry: 245 g lighter (290 g vs 535 g)
  • You need more reach: 50mm vs 40mm at the long end
  • You want bigger close-ups: 0.36× vs 0.21× maximum magnification
  • You want a compact lens: 74.5 mm vs 115.9 mm long

Spec differences

13 differences
Specifications that differ between the Sigma 17-40mm f/1.8 DC and the Sigma 18-50mm f/2.8 DC DN Contemporary
17-40mm f/1.8 DC 18-50mm f/2.8 DC DN Contemporary
Focal length
17-40mm
18-50mm
Max aperture
f/1.8 1⅓ stops faster
f/2.8
Weight
535 g
290 g lighter
Length
115.9 mm
74.5 mm shorter
Diameter
72.9 mm
65.4 mm slimmer
Filter thread
67 mm
55 mm
Min focus distance
0.28 m
not listed
Max magnification
0.21×
0.36× larger
Aperture blades
11 more blades
7
Optical design
17 elements / 11 groups
not listed
Autofocus motor
not listed
Stepping motor
Weather sealing
Yes
not listed
Released
2025
2021
5 identical specs hidden: brand, mount, type, format, image stabilization. Show all
Brand
Sigma both
Mount
Leica L both
Type
Zoom both
Format
APS-C both
Image stabilization
No both

Our notes

Sigma 17-40mm f/1.8 DC

A 17-40mm f/1.8 APS-C fast wide-angle zoom lens, the Sigma 17-40mm f/1.8 DC is designed for Leica L mount bodies. It covers wide angles for landscapes, interiors and architecture.

Our notes

Sigma 18-50mm f/2.8 DC DN Contemporary

More comparisons

Compare other lenses or browse our best-of guides.