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
—
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
ADLinks to Amazon, MPB, Wex Photo Video, Park Cameras, eBay are affiliate links. We may earn a commission if you buy through them, at no extra cost to you.Links to London Camera Exchange are not affiliate links.Links marked “Search results” go to that retailer’s search page for this lens name.Check price and availability on the retailer’s own site.
17-28mm F/2.8 Di III RXD
ADLinks to Amazon, MPB, Wex Photo Video, Park Cameras, eBay are affiliate links. We may earn a commission if you buy through them, at no extra cost to you.Links to London Camera Exchange are not affiliate links.Links marked “Search results” go to that retailer’s search page for this lens name.Check price and availability on the retailer’s own site.
20mm F2 DG in detail17-28mm F/2.8 Di III RXD in detailAll E-mount lenses