Canon RF28-70mm F2.8 IS STMvsSigma 17-40mm F1.8 DC
RF28-70mm F2.8 IS STM
28-70mm / F2.8
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17-40mm F1.8 DC
17-40mm / F1.8
26-60mm equiv.
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Which to choose
When the RF28-70mm F2.8 IS STM suits you better
- Weight65g lighter, so easier to carry
- Zoom rangeCovers 28-70mm in a single lens
- StabilizationHas stabilization
When the 17-40mm F1.8 DC suits you better
- Brightness1.3 stops brighter — better in low light and blurs the background more
- Weather sealingHas weather sealing
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
- RF28-70mm F2.8 IS STM92.2mm long × 76.5mm diameter
- 17-40mm F1.8 DC115.9mm long × 72.9mm diameter
Specifications compared
| Specification | Canon RF28-70mm F2.8 IS STM | Sigma 17-40mm F1.8 DC | Difference |
|---|---|---|---|
| Focal length (wide) | 28mm | 17mm | +11mm |
| Focal length (tele) | 70mm | 40mm | +30mm |
| Max aperture (wide) | F2.8 | F1.8 | 1.3 stops darker |
| Max aperture (tele) | F2.8 | F1.8 | 1.3 stops darker |
| Min aperture | F22 | — | No data |
| Aperture blades | 9blades | — | No data |
| Weight | 495g | 560g | −65g |
| Length | 92.2mm | 115.9mm | −23.7mm |
| Diameter | 76.5mm | 72.9mm | +3.6mm |
| Filter size | 67mm | 67mm | — |
| Released | 2024 | 2025 | −1year |
| Stabilization | Yes | No | Yes |
| Weather sealing | No | Yes | No |
| Macro | No | No | — |
| Autofocus | Yes | Yes | — |
The difference column reads as RF28-70mm F2.8 IS STM relative to 17-40mm F1.8 DC.The highlighted cell is the better side for that specification.
Check prices
RF28-70mm F2.8 IS STM
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17-40mm F1.8 DC
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RF28-70mm F2.8 IS STM in detail17-40mm F1.8 DC in detailAll RF mount lenses