Canon RF 28-70mm f/2 L USM vs Canon RF 400mm f/2.8 L IS USM
The bottom line
These cover different focal lengths — the Canon RF 28-70mm f/2 L USM is 28-70mm, the Canon RF 400mm f/2.8 L IS USM is 400mm — so they're not really substitutes. Pick by the field of view you actually need: the Canon RF 28-70mm f/2 L USM for standard zoom, the Canon RF 400mm f/2.8 L IS USM for super-telephoto.
Choose the Canon RF 28-70mm f/2 L USM if…
- ✓You want more light and background blur — f/2 is faster than f/2.8, better for low light and subject separation.
- ✓You shoot wide — it starts at 28mm vs 400mm for landscapes, interiors and architecture.
- ✓You're on a budget — $3,099 vs $11,999 leaves more for other gear.
- ✓You want one-lens flexibility — a 28-70mm zoom covers what the fixed 400mm can't reframe.
Choose the Canon RF 400mm f/2.8 L IS USM if…
- ✓You need more reach — it goes to 400mm vs 70mm for distant subjects, wildlife and sport.
- ✓You prefer a fast, compact single focal length — a 400mm prime over a zoom.
- ✓You shoot handheld or on an unstabilised body — it has optical stabilisation, the other doesn't.
Where they differ
- ›Aperture: the Canon RF 28-70mm f/2 L USM opens to f/2 vs the Canon RF 400mm f/2.8 L IS USM's f/2.8 — more light and shallower depth-of-field.
- ›Focal range: Canon RF 28-70mm f/2 L USM is 28-70mm, Canon RF 400mm f/2.8 L IS USM is 400mm — different framing and reach.
- ›Type: the Canon RF 28-70mm f/2 L USM is a zoom (flexible framing), the Canon RF 400mm f/2.8 L IS USM a prime (one focal length, usually brighter and lighter).
- ›Price: the Canon RF 28-70mm f/2 L USM is $3,099, $8,900 under the Canon RF 400mm f/2.8 L IS USM.
- ›Stabilisation: only the Canon RF 400mm f/2.8 L IS USM has optical stabilisation — steadier handheld shots, especially on bodies without IBIS.
- ›Weight: the Canon RF 28-70mm f/2 L USM is 1430g (3.15 lb) vs 3450g (7.61 lb) — you'll feel the difference handheld.
Frequently asked
Is the Canon RF 28-70mm f/2 L USM or the Canon RF 400mm f/2.8 L IS USM better?
These cover different focal lengths — the Canon RF 28-70mm f/2 L USM is 28-70mm, the Canon RF 400mm f/2.8 L IS USM is 400mm — so they're not really substitutes. Pick by the field of view you actually need: the Canon RF 28-70mm f/2 L USM for standard zoom, the Canon RF 400mm f/2.8 L IS USM for super-telephoto.
Who should choose the Canon RF 28-70mm f/2 L USM?
Choose the Canon RF 28-70mm f/2 L USM if you want more light and background blur — f/2 is faster than f/2.8, better for low light and subject separation. Choose it if you shoot wide — it starts at 28mm vs 400mm for landscapes, interiors and architecture. Choose it if you're on a budget — $3,099 vs $11,999 leaves more for other gear. Choose it if you want one-lens flexibility — a 28-70mm zoom covers what the fixed 400mm can't reframe.
Who should choose the Canon RF 400mm f/2.8 L IS USM?
Choose the Canon RF 400mm f/2.8 L IS USM if you need more reach — it goes to 400mm vs 70mm for distant subjects, wildlife and sport. Choose it if you prefer a fast, compact single focal length — a 400mm prime over a zoom. Choose it if you shoot handheld or on an unstabilised body — it has optical stabilisation, the other doesn't.
What is the main difference between the Canon RF 28-70mm f/2 L USM and the Canon RF 400mm f/2.8 L IS USM?
Aperture: the Canon RF 28-70mm f/2 L USM opens to f/2 vs the Canon RF 400mm f/2.8 L IS USM's f/2.8 — more light and shallower depth-of-field.
| Product | ||
|---|---|---|
| Optical Design | ||
| Focal Length | 28-70mm | 400mm |
| Lens Type | Zoom | Prime |
| Optical Elements | 19 | 17 |
| Optical Groups | 13 | 13 |
| Aperture & Iris | ||
| Maximum Aperture | f/2 | f/2.8 |
| Minimum Aperture | f/22 | f/32 |
| Aperture Blades | 9 | 9 |
| Rounded Aperture | Yes | Yes |
| Coverage & Angle | ||
| Format Coverage | Full-Frame | Full-Frame |
| Lens Mount | Canon RF | Canon RF |
| Angle of View | 75° – 34° | 6° |
| 35mm Equivalent | − | − |
| Focus | ||
| Autofocus | Yes | Yes |
| Focus Motor | Ring USM | Dual Nano USM |
| Focus Limiter | No | Yes |
| AF/MF Switch | Yes | Yes |
| Min Focus Distance | 39 cm | 250 cm |
| Max Magnification | 0.18x | 0.18x |
| Stabilization & Video | ||
| Optical Stabilization | No | Yes |
| Aperture Ring | No | No |
| Declickable Aperture | No | No |
| Parfocal | No | No |
| Internal Zoom | Yes | No |
| General | ||
| Price (MSRP) | $3,099 | $11,999 |
| Filter Size | 95mm | 52mm |
| Diameter | 103.8mm | 163mm |
| Length | 139.8mm | 343mm |
| Weight | 1430g (3.15 lb) | 3450g (7.61 lb) |
| Weather Sealed | Yes | Yes |
| Tripod Collar | No | Yes |
