HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR § 03 Head to head
HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR vs Sigma 18-50 mm f/2.8-4.5 DC OS HSM
Pentax 20–40mm f/2.8-4 has a brighter maximum aperture. Sigma 18–50mm f/2.8-4.5 has a wider field of view.
The HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR is a 20–40mm f/2.8-4 zoom, and the Sigma 18-50 mm f/2.8-4.5 DC OS HSM is an 18–50mm f/2.8-4.5 zoom. On paper the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR comes out ahead, 7 advantages to 3, but which one suits you depends on what you shoot.
HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR 
Sigma 18-50 mm f/2.8-4.5 DC OS HSM 01
Key differences
Why is the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR better than the Sigma 18-50 mm f/2.8-4.5 DC OS HSM?
- Brighter maximum aperture (f/2.8-4 vs f/2.8-4.5)
- 112 g lighter (283 g vs 395 g)
- 20 mm shorter (68.5 mm vs 88.6 mm long)
- Focuses 2 cm closer (0.28 m vs 0.3 m)
- More aperture blades (9 vs 7)
- Smaller filter thread (55 mm vs 67 mm)
- Newer design (2013 vs 2009)
Why is the Sigma 18-50 mm f/2.8-4.5 DC OS HSM better than the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR?
- Wider field of view (18mm vs 20mm)
- Longer reach (50mm vs 40mm)
- Has optical image stabilization
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Which should you buy?
- landscape For landscape photography, the Sigma 18-50 mm f/2.8-4.5 DC OS HSM has the edge: it goes wider, to 18mm against 20mm.
- architecture For architecture, the Sigma 18-50 mm f/2.8-4.5 DC OS HSM has the edge: it goes wider, to 18mm against 20mm.
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Specification
| Specification | HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR | Sigma 18-50 mm f/2.8-4.5 DC OS HSM |
|---|---|---|
| Focal length | 20–40mm | 18–50mm |
| Maximum aperture | f/2.8-4 ◆ | f/2.8-4.5 |
| Minimum aperture | f/22-32 | f/22 |
| Lens type | Standard zoom lens | Zoom lens |
| Format | APS-C | APS-C |
| Weight | 283 g (10 oz) ◆ | 395 g (13.93 oz) |
| Dimensions | 71 mm (diameter) x 68.5 mm (length) | 74 x 88.6 mm |
| Minimum focusing distance | 0.28 m (11 inches) ◆ | 0.3 m (11.81 inches) |
| Maximum magnification | 0.2x | — |
| Image stabilization | No | Yes ◆ |
| Weather sealing | Yes | — |
| Aperture ring | No | — |
| Aperture blades | 9 (rounded) ◆ | 7 |
| Optical construction | 9 elements in 8 groups (including 1 ED element and 1 super-low dispersion element) | 16 elements in 12 groups |
| Filter size | 55 mm ◆ | 67 mm |
| Lens mount | Pentax K | Nikon F, Sony A, Sigma SA, Pentax K, Canon EF-S |
| Released | 2013 | 2009 |
04
Size
- A · HD
- B · Sigma
- 68.5 × 71 mm
- 88.6 × 74 mm
The Sigma 18-50 mm f/2.8-4.5 DC OS HSM is 20 mm longer and 112 g heavier than the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR.
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Sample frames
Sigma 18-50 mm f/2.8-4.5 DC OS HSM
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Video reviews
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Questions
- Which lens has the brighter aperture, the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR or the Sigma 18-50 mm f/2.8-4.5 DC OS HSM?
- The HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR opens to f/2.8-4, against f/2.8-4.5 on the Sigma 18-50 mm f/2.8-4.5 DC OS HSM.
- Which is lighter, the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR or the Sigma 18-50 mm f/2.8-4.5 DC OS HSM?
- The HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR weighs 283 g, 112 g less than the Sigma 18-50 mm f/2.8-4.5 DC OS HSM (395 g).
- Which focuses closer, the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR or the Sigma 18-50 mm f/2.8-4.5 DC OS HSM?
- The HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR focuses down to 0.28 m, against 0.3 m for the Sigma 18-50 mm f/2.8-4.5 DC OS HSM.
- Do the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR and the Sigma 18-50 mm f/2.8-4.5 DC OS HSM have image stabilization?
- Only the Sigma 18-50 mm f/2.8-4.5 DC OS HSM has optical image stabilization.
- Is the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR or the Sigma 18-50 mm f/2.8-4.5 DC OS HSM better for landscape photography?
- For landscape photography, the Sigma 18-50 mm f/2.8-4.5 DC OS HSM has the edge: it goes wider, to 18mm against 20mm.
- Is the HD Pentax-DA 20-40mm f/2.8-4 ED Limited DC WR or the Sigma 18-50 mm f/2.8-4.5 DC OS HSM better for architecture?
- For architecture, the Sigma 18-50 mm f/2.8-4.5 DC OS HSM has the edge: it goes wider, to 18mm against 20mm.