Tamron 70-300mm F/4.5-6.3 Di III RXD vs Sigma 100-400mm f/5-6.3 DG DN OS Contemporary
Both are Sony E telephoto zoom lenses for full frame. Here is what actually differs.

Pick the Tamron 70-300mm F/4.5-6.3 Di III RXD if
- You need ⅓ stop more light for low light or background blur (f/4.5 vs f/5)
- You want the lighter lens to carry: 595 g lighter (545 g vs 1140 g)
- You want a wider view: 70mm vs 100mm at the wide end
- You want a compact lens: 148 mm vs 199.2 mm long
- Our notes say it suits: Casual wildlife, sports in daylight, travel
Pick the Sigma 100-400mm f/5-6.3 DG DN OS Contemporary if
- You need more reach: 400mm vs 300mm at the long end
- You shoot handheld in dim light or video: it has optical image stabilization and the Tamron 70-300mm F/4.5-6.3 Di III RXD does not
- You want bigger close-ups: 0.24× vs 0.2× maximum magnification
- You care about the shape of out-of-focus highlights: 9 aperture blades vs 7
Spec differences
12 differences| Tamron 70-300mm F/4.5-6.3 Di III RXD | Sigma 100-400mm f/5-6.3 DG DN OS Contemporary | |
|---|---|---|
| Brand |
Tamron
|
Sigma
|
| Focal length |
70-300mm
|
100-400mm
|
| Max aperture |
f/4.5
⅓ stop faster
|
f/5
|
| Weight |
545 g
lighter
|
1140 g
|
| Length |
148 mm
shorter
|
199.2 mm
|
| Diameter |
77 mm
slimmer
|
86 mm
|
| Min focus distance |
0.8 m
|
not listed
|
| Max magnification |
0.2×
|
0.24×
larger
|
| Aperture blades |
7
|
9
more blades
|
| Optical design |
15 elements / 10 groups
|
22 elements / 16 groups
|
| Autofocus motor |
RXD
|
not listed
|
| Image stabilization |
No
|
Yes
stabilized
|
6 identical specs hidden: mount, type, format, filter thread, weather sealing, released. Show all
- Mount
- Sony E both
- Type
- Telephoto Zoom both
- Format
- Full frame both
- Filter thread
- 67 mm both
- Weather sealing
- Yes both
- Released
- 2020 both
Our notes
Tamron 70-300mm F/4.5-6.3 Di III RXD
Compact telephoto zoom for Sony full-frame covering 70-300mm. It has no stabilization and weighs about 545 g.
Pros
- Light at about 545 g
- Compact
- RXD focus motor
Cons
- No lens stabilization
- Slow aperture
Our notes
Sigma 100-400mm f/5-6.3 DG DN OS Contemporary
More comparisons

Sony E 55-210mm F4.5-6.3 OSS vs Tamron 70-300mm F/4.5-6.3 Di III RXD
200 g lighter vs more reach (300mm)

Tamron 150-500mm F/5-6.7 Di III VC VXD vs Sigma 100-400mm f/5-6.3 DG DN OS Contemporary
more reach (500mm) vs 585 g lighter
Sony E 70-350mm F4.5-6.3 G OSS vs Tamron 70-300mm F/4.5-6.3 Di III RXD
more reach (350mm) vs 80 g lighter


Sony E 55-210mm F4.5-6.3 OSS vs Sigma 100-400mm f/5-6.3 DG DN OS Contemporary
⅓ stop faster vs more reach (400mm)

Sony E 70-350mm F4.5-6.3 G OSS vs Sigma 100-400mm f/5-6.3 DG DN OS Contemporary
⅓ stop faster vs more reach (400mm)

Tamron 70-300mm F/4.5-6.3 Di III RXD vs Sigma 150-600mm f/5-6.3 DG DN OS Sports
⅓ stop faster vs more reach (600mm)