Bringing EF and EF-S lenses to the EOS R System

The launch of the EOS R System with the Canon EOS R combined the best of the heritage of the Canon EOS range with the innovations of full-frame mirrorless technology, along with a suite of new RF lenses. For existing Canon shooters using EF and EF-S lenses, the transition to full-frame mirrorless has been helped by the selection of EF-EOS R mount adapters available, which not only allow these lenses to work seamlessly on EOS R System cameras, but add functionality and even improve the optical performance of lenses.

Fashion and portrait photographer Guia Besana, who exhibits across the globe and has published images in Le Monde, Newsweek and Marie Claire, regularly puts her collection of EF lenses to work on her Canon EOS R, using a mount adapter. Destination wedding photographer Katya Mukhina also appreciates the flexibility a mount adapter gives her with her kitbag, which includes a Canon EOS R. "I continue to use certain EF lenses because their lens characteristics are so unique," she says. "I'm also still using my Canon EOS-1D X Mark II [now succeeded by the Canon EOS-1D X Mark III], so keeping some EF lenses in my bag is more functional."

As the EOS R System family continues to grow, these two Canon Ambassadors share how they pair non-RF lenses with EOS R System cameras in the field, while Canon Europe Product Specialist Mike Burnhill outlines the specific features of Canon's three EF-EOS R mount adapters.

Using EF-EOS R adapters

Offering full compatibility with Canon EF and EF-S lenses, all three EF-EOS R mount adapters enable photographers and filmmakers to continue to make full use of their existing lenses. The standard Mount Adapter EF-EOS R is Guia's adapter of choice, which she finds gives her everything she needs. "I have lots of different EF lenses and want to be able to use them," she explains. "The Canon EF 40mm f/2.8 STM lens is a good example because it makes the camera light and small to carry around for shots that I usually use as notes, in a reportage style."

The Control Ring Mount Adapter EF-EOS R adds a Lens Control Ring to the mount conversion, which enables users to customise functionality and adjust settings without taking their eye off the camera. It can be programmed to adjust shutter speed, aperture, ISO, exposure compensation or white balance. Positive or negative values can be assigned to either a left or right turn of the ring, and there's also the option of engaging the control ring setting only when half pressing the shutter release button to avoid accidentally adjusting settings during crucial moments.

Full creative flexibility

When working on personal projects, Guia likes to be able to use her EF lenses in tandem with RF lenses. "I usually use a Canon RF 50mm F1.2L USM lens with the Canon EOS R, which I mount on a tripod," she says. "I then like to shift to EF lenses, such as the Canon EF 100mm f/2.8L Macro IS USM lens, and use it hand-held to explore a different point of view.

"Using the RF and EF lenses together has made me consider different ways of moving around a subject during the same session – something I wasn't really doing before."

Being able to stick with the same camera whichever lenses she chooses, she adds, also makes her post-processing workflow easier, as the files are consistent from the one camera.

A bilingual system which enhances performances

The EF-EOS R mount adapters are unique because they don't confuse the signal running between the lens and camera body, says Mike, which allows the camera to communicate directly with the lens whether it's EF or RF – making for a "bilingual" system.

"Most adapters physically and electronically convert signals from one device to another," he says. "Information gets lost in translation, which is when things lock up and stop working. The EF-EOS R mount adapters are just a pass-through, so there's no performance drop. The camera then cleverly notices the lens that's attached to the adapter and communicates with the lens. Third-party adapters have firmware to communicate intelligently between lens and body, but this all takes time. With the Canon system there's very minimal latency, so it works – quickly and reliably."

So well does it work that, out of the 150 or so EF lenses Canon has produced, only eight older lenses do not retain full functionality when used with EF-EOS R mount adapters: the power zoom button does not work on the Canon EF 35-80mm f/4-5.6 PZ (1991), and the AF stop button does not work on seven, largely discontinued, lenses.* All other functions operate without a problem.

What's more, the technology behind the adapters can actually enhance the performance of EF and EF-S lenses. These lenses perform just as well on the EOS R System as they did with their original counterparts, if not even better, says Mike. "An EOS R System body uses a bigger list of built-in lens profiles, so it can automatically correct for more lens aberrations in-camera, producing better pictures straight out of the camera."