The Canon RF 24-70mm f/2.8 L IS USM is the practical standard zoom, while the RF 28-70mm f/2 L USM is a specialist lens built around an unusually wide constant aperture. Choose the 24-70 for everyday flexibility, a wider view and easier carrying; choose the 28-70 f/2 when shallow depth of field and low-light performance matter more than size. Confirm exact specs on Canon’s product pages.
What Sets Them Apart
Both lenses keep a constant aperture across the zoom range, which means your exposure settings stay put as you zoom. The difference is how wide that aperture is. An f/2 aperture lets in roughly twice the light of f/2.8, which allows faster shutter speeds or lower ISO in dim rooms, and it gives a softer background at the same framing.
The cost is size and handling. A lens with a very wide zoom aperture needs large glass, so the 28-70 f/2 is a bigger lens than the 24-70 f/2.8 and is meant for people who want that look badly enough to carry it. The 24-70 also opens a touch wider, with a 24mm view that suits interiors, groups and landscapes.
Comparison Table
| Trait | RF 24-70mm f/2.8 | RF 28-70mm f/2 |
|---|---|---|
| Wide end | 24mm | 28mm |
| Constant aperture | f/2.8 | f/2 |
| Image stabilization in the lens | Yes | Check Canon’s page |
| Size and carry | More compact | Larger, more deliberate |
| Strength | All-round flexibility | Low light and background blur |
Who Should Choose Which
- Choose the 24-70 f/2.8 if you shoot events, travel, family and landscape work and want one lens that is comfortable to carry all day.
- Choose the 28-70 f/2 if you shoot portraits, weddings in dim venues, or video where a wide aperture and shallow focus are a core part of your look.
- Choose the 24-70 if you often need a very wide frame for rooms or groups. The extra 4mm at the wide end is noticeable.
- Choose the 28-70 if you would otherwise carry several fast prime lenses and want one zoom to replace some of them.
Working With a Very Wide Aperture
These are general baselines, not fixed rules. At f/2, depth of field is thin, so focus accuracy matters.
- For a single portrait subject, try an aperture of roughly f/2 to f/2.8 and focus on the nearer eye.
- For two people, close down to around f/4 so both faces stay sharp.
- In dim rooms, keep the shutter speed at roughly 1/125 or faster for people who are moving a little, and raise ISO only as needed.
- In bright sun, a wide aperture can push the shutter speed past the camera limit, so a neutral density filter or a smaller aperture may be needed.
FAQ
Is f/2 versus f/2.8 a big difference?
It is one full stop, which means roughly double the light gathered, and a visibly softer background when you are close to your subject. For distant scenes the look changes very little.
Can the 24-70 f/2.8 handle portraits?
Yes. At the long end and a wide aperture it gives pleasing background separation for most portrait work, just not as much as an f/2 lens.
The Short Version
The RF 24-70mm f/2.8 is the sensible do-everything standard zoom, and the RF 28-70mm f/2 is for shooters who want prime-like light gathering in a zoom. Choose by what you value more: carrying ease and range, or the widest aperture available.
