Canon RF 100-400mm f/5.6-8 IS USM vs Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)
The bottom line
Similar coverage, different speed: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) opens to f/3.5 versus the Canon RF 100-400mm f/5.6-8 IS USM's f/5.6 — more light and shallower background blur. It comes down to how much you value that extra brightness.
Choose the Canon RF 100-400mm f/5.6-8 IS USM if…
- ✓You need more reach — it goes to 400mm vs 300mm for distant subjects, wildlife and sport.
Choose the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) if…
- ✓You want more light and background blur — f/3.5 is faster than f/5.6, better for low light and subject separation.
- ✓You shoot wide — it starts at 18mm vs 100mm for landscapes, interiors and architecture.
- ✓You work outdoors — it's weather-sealed against dust and moisture; the other isn't.
Where they differ
- ›Aperture: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) opens to f/3.5 vs the Canon RF 100-400mm f/5.6-8 IS USM's f/5.6 — more light and shallower depth-of-field.
- ›Focal range: Canon RF 100-400mm f/5.6-8 IS USM is 100-400mm, Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) is 18-300mm — different framing and reach.
- ›Durability: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) is weather-sealed; the other isn't.
Frequently asked
Is the Canon RF 100-400mm f/5.6-8 IS USM or the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) better?
Similar coverage, different speed: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) opens to f/3.5 versus the Canon RF 100-400mm f/5.6-8 IS USM's f/5.6 — more light and shallower background blur. It comes down to how much you value that extra brightness.
Who should choose the Canon RF 100-400mm f/5.6-8 IS USM?
Choose the Canon RF 100-400mm f/5.6-8 IS USM if you need more reach — it goes to 400mm vs 300mm for distant subjects, wildlife and sport.
Who should choose the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)?
Choose the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) if you want more light and background blur — f/3.5 is faster than f/5.6, better for low light and subject separation. Choose it if you shoot wide — it starts at 18mm vs 100mm for landscapes, interiors and architecture. Choose it if you work outdoors — it's weather-sealed against dust and moisture; the other isn't.
What is the main difference between the Canon RF 100-400mm f/5.6-8 IS USM and the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF)?
Aperture: the Tamron 18-300mm F/3.5-6.3 Di III-A VC VXD (Canon RF) opens to f/3.5 vs the Canon RF 100-400mm f/5.6-8 IS USM's f/5.6 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 100-400mm | 18-300mm |
| Lens Type | Zoom | Zoom |
| Optical Elements | 18 | 19 |
| Optical Groups | 12 | 15 |
| Aperture & Iris | ||
| Maximum Aperture | f/5.6 | f/3.5 |
| Minimum Aperture | f/32 | f/22 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | Full-Frame | APS-C |
| Lens Mount | Canon RF | Canon RF |
| Angle of View | 24° – 6° | 76° – 5.2° |
| 35mm Equivalent | − | 29-480mm |
| Focus | ||
| Autofocus | Yes | Yes |
| Focus Motor | Nano USM | VXD |
| Focus Limiter | No | No |
| AF/MF Switch | Yes | No |
| Min Focus Distance | 88 cm | 15 cm |
| Max Magnification | 0.41x | 0.5x |
| Stabilization & Video | ||
| Optical Stabilization | Yes | Yes |
| Aperture Ring | No | No |
| Declickable Aperture | No | No |
| Parfocal | No | No |
| Internal Zoom | No | No |
| General | ||
| Price (MSRP) | $649 | $629 |
| Filter Size | 67mm | 67mm |
| Diameter | 79mm | 75.5mm |
| Length | 147mm | 123.6mm |
| Weight | 635g (1.40 lb) | 620g (1.37 lb) |
| Weather Sealed | No | Yes |
| Tripod Collar | No | No |
