Canon EOS R’s Autofocus is a Massive Advancement in Canon Tech

After the news of the Canon EOS R’s announcement settled, I kept coming back to a few of the features. I think it is pretty special in some key ways. The most striking advancement in my eyes is the ability to autofocus at f/11.

For those that have never needed this feature, what exactly does AF at f/11 mean?

When you take a telephoto lens like the Canon EF 100-400mm f/4.5-5.6L IS II USM lens, your max aperture at 400mm is f/5.6. The most light the AF sensor can receive when zoomed to 400mm is from the small-ish f/5.6 aperture. Now, add a 1.4x teleconverter and you lose a stop of light. You end up with 560mm at effectively f/8 on the telephoto end. Previously, that’s the best a Canon DSLR could offer.

Now, you can add a 2x teleconverter to the Canon EOS R and the EF 100-400mm f/4.5-5.6L IS II USM lens. This combo loses two stops of light and yields an effective max zoom of 800mm at f/11 in a relatively compact package. That’s the power of the tech inside the Canon EOS R’s autofocus system.

For years, Canon struggled to deliver a camera with an AF system that offer autofocus flexibility above f/5.6 (e.g., Canon 1D X). So many cameras were limited to center AF point for f/8, or they simply didn’t offer autofocus above f/5.6. In some cases, Canon was forced to add the feature via a firmware update after launch.

While Canon has made strides in the AF department in recent models, nothing has really knocked our socks off. That is, until the announcement of the EOS R and the claims it makes with the new AF system that allows users to shoot over nearly the entire image area even with effective apertures at f/11.

I’m not a bird photographer but I understand that bird and wildlife shooters need that extra dose of AF accuracy and control beyond f/5.6 at times. While I haven’t used the Canon EOS R yet, I’m cautiously optimistic that the real world function lives up to the ambitious spec sheet.

Canon repeatedly claims that EF lenses suffer virtually no performance loss when attached via the EOS R lens adapter. If that’s the case, the EOS R could be a very exciting camera for wildlife photographers while they await the arrival of a true professional grade camera in the EOS R product line. And that’s another important point to note about the EOS R – Canon considers it a prosumer model. That means it is effectively slotted around the Canon 6D Mark II on the DSLR side.

Notably, the inclusion of the UHS-II (about time) SD card slot suggest that it has the chops to handle a moderate array of burst shooting that should appeal to wildlife and sports enthusiasts and pros alike. Of course, the single memory card slot is a no-go for what I believe is a vocal minority. Personally, I don’t think the lack of two card slots will materially affect the overall sales of the Canon EOS R. As an aside, if you’re not familiar with why UHS-II is important and what it means for the EOS R, you can learn more about it here.

Canon has delivered so much vanilla in recent years. While the EOS R still feels like a “safe” play in terms of a full frame mirrorless camera launch, I think there is quite a bit to be happy about – starting with autofocus at f/11. It’s too early to really call it a game changer; however, I feel like this development is getting overlooked in much of the early reports that criticize the 4K crop video capture and single card slot.

I’m going to try to get my hands on the Canon EOS R when commercial units are available and start digging into some of the new features. In the mean time, are you considering picking up the Canon EOS R? What features stand out to you on the new camera?