Sigma 20mm F2 DGvsTamron 17-28mm F/2.8 Di III RXD
20mm F2 DG
20mm / F2
—
17-28mm F/2.8 Di III RXD
17-28mm / F2.8
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Which to choose
When the 20mm F2 DG suits you better
- Brightness1.0 stops brighter — better in low light and blurs the background more
- Weight50g lighter, so easier to carry
When the 17-28mm F/2.8 Di III RXD suits you better
- Zoom rangeCovers 17-28mm in a single lens
These points are derived mechanically from the numbers. How a lens actually renders does not show up in specifications, so look at samples before deciding.
Size compared
- 20mm F2 DG74.4mm long × 70mm diameter
- 17-28mm F/2.8 Di III RXD99mm long × 73mm diameter
Specifications compared
| Specification | Sigma 20mm F2 DG | Tamron 17-28mm F/2.8 Di III RXD | Difference |
|---|---|---|---|
| Focal length (wide) | 20mm | 17mm | +3mm |
| Focal length (tele) | 20mm | 28mm | −8mm |
| Max aperture (wide) | F2 | F2.8 | 1.0 stops brighter |
| Max aperture (tele) | F2 | F2.8 | 1.0 stops brighter |
| Min aperture | — | F22 | No data |
| Min focus distance | — | 19cm | No data |
| Max magnification | — | 0.19× | No data |
| Aperture blades | — | 9blades | No data |
| Weight | 370g | 420g | −50g |
| Length | 74.4mm | 99mm | −24.6mm |
| Diameter | 70mm | 73mm | −3mm |
| Filter size | 62mm | 67mm | −5mm |
| Released | 2025 | 2019 | +6year |
| Stabilization | No | No | — |
| Weather sealing | Yes | Yes | — |
| Macro | No | No | — |
| Autofocus | Yes | Yes | — |
The difference column reads as 20mm F2 DG relative to 17-28mm F/2.8 Di III RXD.The highlighted cell is the better side for that specification.
Check prices
20mm F2 DG
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17-28mm F/2.8 Di III RXD
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20mm F2 DG in detail17-28mm F/2.8 Di III RXD in detailAll E-mount lenses