Sigma 100-400mm f/5-6.3 DG DN OS Contemporary vs Tamron 17-28mm F/2.8 Di III RXD
The bottom line
These cover different focal lengths — the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary is 100-400mm, the Tamron 17-28mm F/2.8 Di III RXD is 17-28mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary for super-telephoto, the Tamron 17-28mm F/2.8 Di III RXD for wide-angle zoom.
Choose the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary if…
- ✓You need more reach — it goes to 400mm vs 28mm for distant subjects, wildlife and sport.
- ✓You shoot handheld or on an unstabilised body — it has optical stabilisation, the other doesn't.
Choose the Tamron 17-28mm F/2.8 Di III RXD if…
- ✓You want more light and background blur — f/2.8 is faster than f/5, better for low light and subject separation.
- ✓You shoot wide — it starts at 17mm vs 100mm for landscapes, interiors and architecture.
- ✓You value portability — at 420g (14.8 oz) it's lighter than the 1140g (2.51 lb) alternative for travel and all-day carry.
Where they differ
- ›Aperture: the Tamron 17-28mm F/2.8 Di III RXD opens to f/2.8 vs the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary's f/5 — more light and shallower depth-of-field.
- ›Focal range: Sigma 100-400mm f/5-6.3 DG DN OS Contemporary is 100-400mm, Tamron 17-28mm F/2.8 Di III RXD is 17-28mm — different framing and reach.
- ›Stabilisation: only the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary has optical stabilisation — steadier handheld shots, especially on bodies without IBIS.
- ›Weight: the Tamron 17-28mm F/2.8 Di III RXD is 420g (14.8 oz) vs 1140g (2.51 lb) — you'll feel the difference handheld.
Frequently asked
Is the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary or the Tamron 17-28mm F/2.8 Di III RXD better?
These cover different focal lengths — the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary is 100-400mm, the Tamron 17-28mm F/2.8 Di III RXD is 17-28mm — so they're not really substitutes. Pick by the field of view you actually need: the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary for super-telephoto, the Tamron 17-28mm F/2.8 Di III RXD for wide-angle zoom.
Who should choose the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary?
Choose the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary if you need more reach — it goes to 400mm vs 28mm for distant subjects, wildlife and sport. Choose it if you shoot handheld or on an unstabilised body — it has optical stabilisation, the other doesn't.
Who should choose the Tamron 17-28mm F/2.8 Di III RXD?
Choose the Tamron 17-28mm F/2.8 Di III RXD if you want more light and background blur — f/2.8 is faster than f/5, better for low light and subject separation. Choose it if you shoot wide — it starts at 17mm vs 100mm for landscapes, interiors and architecture. Choose it if you value portability — at 420g (14.8 oz) it's lighter than the 1140g (2.51 lb) alternative for travel and all-day carry.
What is the main difference between the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary and the Tamron 17-28mm F/2.8 Di III RXD?
Aperture: the Tamron 17-28mm F/2.8 Di III RXD opens to f/2.8 vs the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary's f/5 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 100-400mm | 17-28mm |
| Lens Type | Zoom | Zoom |
| Optical Elements | 22 | 13 |
| Optical Groups | 16 | 12 |
| Aperture & Iris | ||
| Maximum Aperture | f/5 | f/2.8 |
| Minimum Aperture | f/32 | f/22 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | Full-Frame | Full-Frame |
| Lens Mount | Sony E | Sony E |
| Angle of View | 24° – 6° | 104° – 75° |
| 35mm Equivalent | − | − |
| Focus | ||
| Autofocus | Yes | Yes |
| Focus Motor | HLA | RXD |
| Focus Limiter | Yes | No |
| AF/MF Switch | Yes | Yes |
| Min Focus Distance | 120 cm | 19 cm |
| Max Magnification | 0.24x | 0.19x |
| Stabilization & Video | ||
| Optical Stabilization | Yes | No |
| Aperture Ring | No | No |
| Declickable Aperture | No | No |
| Parfocal | No | No |
| Internal Zoom | No | No |
| General | ||
| Price (MSRP) | $759 | $799 |
| Filter Size | 67mm | 67mm |
| Diameter | 86mm | 73mm |
| Length | 196.6mm | 99mm |
| Weight | 1140g (2.51 lb) | 420g (14.8 oz) |
| Weather Sealed | Yes | Yes |
| Tripod Collar | No | No |
