(Editor’s Note: Ryan Hill is a product specialist at Lensrentals.)
Here’s a fun fact: Canon’s EF lens mount system is almost exactly as old as I am. I was born in December of 1987, and Canon launched its first EF mount camera, the EOS 650 film SLR, just three months later. At the time, it was Canon’s first new lens mount in nearly 20 years, and now, 33 years later, it and I are still kicking. One of us, though, is starting to lose some relevancy.
Canon introduced the RF lens mount alongside the new EOS R full frame mirrorless camera system in 2018 and has since devoted most of its new development output to that format. The official word from Canon is that design of new EF lenses has been paused indefinitely in favor of releasing more RF lenses, and those new RF lenses are coming in at an impressive clip. Canon’s first-party RF lineup currently stands at sixteen lenses, with many more already announced.
That isn’t to say that Canon’s EF lens line is already dead, though. Despite constant rumors to the contrary, Canon is still officially manufacturing most of its existing EF line. Plus, given existing stock and the still-active used market, even if Canon announced tomorrow it was immediately ceasing all EF lens production, it’d remain relatively easy to be an EF-only photographer well into the future, even if you’re working on an RF body with adapters.
So, while the transition to RF lenses may be inevitable, it certainly won’t be instant or cheap. Most Canon shooters will probably adopt a piecemeal approach: first upgrading their body and shooting with adapters, then upgrading their trusted EF lenses to their new RF equivalents as necessary. How, then do you decide what to upgrade first? Which lenses are worth the investment?
To try to help answer those questions, here’s a feature comparison between a few of Canon’s most popular EF lenses and their respective RF mount replacements.
Starting with the obvious, Canon’s RF version of the 24-70 has 5-axis optical image stabilization. That may not be an essential feature for everyone, but for wedding photographers, photojournalists, or anyone else for whom the 24-70 is an indispensable workhorse, it could be a huge plus. People who absolutely need a 24-70 are often shooting handheld with available light, and in that circumstance the ability to shoot at a slower shutter speed without having to set up a tripod could be the difference between getting or missing the shot.
Optically the RF 24-70 seems to be on par with the EF version, which is arguably the highest resolving mid-range zoom ever made. Depending on focal length, the RF may even be slightly sharper in the corners.
Bokeh appearance is also similar, with both lenses displaying circular bokeh thanks to their nine rounded aperture blades. Vignetting is a little more noticeable on the RF version than on the EF, but, in my experience, nothing that can’t be compensated for in post. In short, if you’re happy with the optical performance of the EF 24-70, you’ll likely be happy with the RF and vice versa.
Autofocus is another area in which the RF 24-70 has a leg up over the EF version. The new Nano USM system on the RF, though it sounds like marketing nonsense, really does have a noticeable effect on AF sound level and speed, especially in continuous modes. Paired with a Canon EOS R5 camera, I also found the RF lens to be markedly better at face and eye tracking than the EF.
Those improvements do come at a cost, though. Unlike the EF version, the RF 24-70 is entirely focus by wire, meaning the focus ring has no mechanical control over the lens. All focusing is done electronically.
While some might understandably consider this a downgrade, I’ve personally come to prefer it. After some practice with the lens and a little digging in the menus to dial in your preferred settings, the feel isn’t nearly as jarring as it can seem at first. And the flexibility allowed by a focus by wire system can be worth the learning curve.
The user can adjust the rate of focus change on the RF lens, for example, or even temporarily engage manual focus during AF modes without flipping the switch on the lens body. The RF version also has about a 7-inch closer minimum focusing difference than the EF.
Part of the reason Canon introduced a new lens mount alongside their transition to mirrorless bodies was to allow more flexibility in lens design. The shorter flange focal distance on the RF mount allows rear elements to be much closer to the sensor, thereby requiring fewer focusing elements in the lens, which can make for lighter, shorter lenses. Nowhere is that potential more apparent than in the Canon RF 70-200 f/2.8L IS lens.
While it is possible to hand hold an EF 70-200 f/2.8 on a DSLR body like a Canon EOS 5D IV, it’s not the most comfortable experience. Even with the capable IS, shutter speeds are going to be limited, especially at 200mm. Put that same lens on a Canon R5 with an inch-thick adapter and it’s almost unusable without a tripod. In practice not only is it difficult to operate, it even feels like you could damage the mount.
Swapping to a native RF mount 70-200 on an R5 is a night and day difference. While the numbers might not sound all that impressive (about a pound lighter and about two inches shorter, not including the adapter), the actual experience of shooting with the RF is far, far more enjoyable.
Admittedly, the RF version does have a telescoping barrel, which is something a lot of photographers dislike and isn’t an issue with the EF version. It doesn’t extend far, though, and doesn’t affect the balance much, so I was never bothered by it during my time with the lens. It is something to be aware of, though.
Like the 24-70s, the optical differences between the EF and RF 70-200 are minimal. In short, the 70-200 is better by most measurable metrics but not by so much that’ll be immediately noticeable under most circumstances. Corner sharpness is slightly better, especially at longer focal lengths, and autofocus is quite a bit faster.
The important point, though, is that Canon achieved these results in tandem with a much more manageable form factor. Between the three lenses covered here, this is the one I’d recommend upgrading first if you use a 70-200 with an adapter on an RF body.
While the 50mm f/1.2 might not be part of every photographer’s kit, there’s a certain subset of pros who would consider it a must, especially for portraits. If you’re one of those, you can rest easy knowing that the EF 50mm f/1.2 probably isn’t the first lens in your kit that you’ll need to rush out and upgrade.
Beginning with the similarities between the two lenses, the bokeh, which is the primary reason for shooting on a lens this fast, is gorgeous on both versions. Both versions are also USM lenses, meaning they both focus by wire. While that isn’t necessarily an advantage, it’s at least a commonality, one less thing to learn if and when you do make the switch.
The RF 50mm f/1.2, in my experience, does have a few optical advantages. Corner bokeh fringing and chromatic aberration, which are noticeable on the EF version, are much less prevalent. The RF version is also slightly sharper wide open, but not significantly, and still less sharp than the slightly slower EF Sigma 50mm f/1.4.
In short, the differences are there if you’re looking for them, but they’re not as immediately noticeable as the differences between the RF and EF versions of the 24-70 or 70-200. If I were a photographer with an RF body and these three EF lenses in my bag, the 50mm f/1.2 would be the one I upgraded last.