The benefits of using Canon RF lenses for video

A filmmaker changing an RF lens on the Canon EOS R5.
Canon's innovative RF lenses offer super-fast focusing and outstanding optical quality, making them an ideal option for filmmakers. © Martin Bissig

When the Canon EOS R System was being developed, the design of the RF lenses came first. Canon's engineers set out to create the ideal lens, and the new RF lens mount combined with the Canon EOS R System's full-frame mirrorless architecture allowed them to realise their goal.

The RF mount enables a new freedom in lens design, where large apertures, high resolving power and cutting-edge components are combined to create unique optics for shooting video and stills. It's not just the exceptional image quality of RF lenses that leaves a lasting impression – they are beautiful to use, too. The 12-pin RF mount expands the quantity and speed of communication between the lens and the camera, bringing an enhanced level of autofocus, image stabilisation and customisable control that make RF lenses the perfect choice for video capture.

Four RF lenses were available at the launch of the Canon EOS R System in 2018 and the range of RF zooms and primes now stands at 15 – and rising. Recent launches include the versatile Canon RF 85mm F2 Macro IS STM and Canon RF 100-500mm F4.5-7.1 L IS USM lenses, plus the revolutionary Canon RF 600mm F11 IS STM and Canon RF 800mm F11 IS STM super-telephotos.

With its game-changing 8K video and 45MP photo resolution, the Canon EOS R5 sets a new benchmark for full-frame hybrid camera performance. But it wouldn't have been possible to realise some of the Canon EOS R5's uncompromising capabilities if it wasn't for the RF mount.

Here, we look at some of the benefits that RF lenses can bring for videographers.

Filmmaker Ivan D'Antonio stands behind a tripod mounted with a Canon EOS R5.
Ivan D'Antonio and Martin Bissig (pictured right) were two of the first pros to test the Canon EOS R5 and RF lenses' filmmaking capabilities. © Ivan D'Antonio
Filmmaker Martin Bissig holding the Canon EOS R5 fitted with an RF lens.
Combining the Canon EOS R5 with an IS-equipped RF lens makes it possible to capture shake-free footage, even when shooting handheld. "I use all the Canon RF lenses that are equipped with stabilisation, and the IS performs so well," says Martin. © Martin Bissig
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1. Breakthrough design for unrivalled image quality

RF lenses share the same large 54mm internal diameter as Canon's EF lenses, but they have a shorter flange distance from the mount to the camera sensor.

"When the engineers were creating design mock-ups, they realised that the existing EF mount diameter is actually perfect," reveals Ram Sarup, Pro Video Product Specialist at Canon Europe. "But without a mirror assembly, the distance between the rear element of the lens and the focal plane of an EOS R System camera's sensor is reduced to just 20mm. That's less than half the flange distance in an EOS DSLR. This means we can now have larger apertures for a given focal length and achieve corner to corner sharpness with minimal light falloff."
The Canon EOS R5 on a tripod with a filter attached to the lens to shoot video.
"The data that's being transferred back and forth between the body and the lens – the focusing information, zoom information, aperture, camera shake and optical correction, the lens aberration correction data – is all transferred very quickly between the lens and the body via the 12-pin connection," explains Ram Sarup, Pro Video Product Specialist at Canon Europe. © Ivan D'Antonio

2. Faster communication

Compared with the 8-pin EF mount, the RF mount's 12-pin connection provides more communication power between the lens and the camera. This enables a number of improvements, such as more responsive autofocus and real-time Digital Lens Optimisation (DLO).

The faster communication also enables a sophisticated level of image stabilisation. Both the Canon EOS R5 and Canon EOS R6 feature in-body Image Stabilization (IBIS) which works in co-ordination with an IS lens to deliver up to 8-stops of stability. IBIS also adds stabilisation for those shooting with non-IS lenses.

"Gimbals will always have a place," says Ram. "If you're sprinting after an athlete or if you're working with the camera mounted to a vehicle, for example, then a gimbal will do a better job than any human being could when shooting handheld. But for typical run-and-gun filming, most people would find the new level of IS to be more than sufficient. If you're using a telephoto RF lens, you'll certainly see a huge difference with the Canon EOS R5 and Canon EOS R6."

Martin Bissig filming a skateboarder with the Canon EOS R5.
"The key benefit of using an RF lens with the stabilisation system in the Canon EOS R5 and Canon EOS R6 is that they work hand in hand," says Ram. "It knows exactly which lens you have mounted, so it can pick the best profile for optimised performance." © Martin Bissig
A mountain biker mid-stunt and upside down, silhouetted against the sky and framed by trees.
"If you mount an EF 70-200mm lens on an EOS DSLR, Cinema EOS camera or EOS R System camera (via an adapter), you get some focus breathing when you shift the focus between objects in the foreground and background. The RF 70-200mm F2.8L IS USM lens reduces this significantly," says Ram. © Martin Bissig

3. Focusing designed for video

The large elements used in a fast RF lens result in a heavier focus group, but the Nano USM or Dual Nano USM actuators offer a powerful, compact and quiet way to drive autofocus that's ideal for shooting movies. The STM AF actuator employed in other RF lenses gives smooth, near-silent focusing that's a real benefit when recording audio with a camera-mounted microphone.

Filming 8K and oversampled 4K on the Canon EOS R5

Filming 8K and oversampled 4K on the Canon EOS R5

In the first Canon EOS R5 video shoots, Martin Bissig and Ivan D'Antonio explored how its 8K capabilities reduce shooting time and expand creative options.

"While there may still be people who are apprehensive about using autofocus for filmmaking, we've introduced many useful features into cameras that enable filmmakers to start to rely on the autofocus capabilities," says Ram. "If you're a solo shooter, Dual Pixel CMOS AF is a godsend. Filmmakers have come back to us to say how accurate they've found it, and how the image doesn't snap into focus with that obvious digital look."

RF lenses use a focus-by-wire system for manual focusing, but the speed at which the lens and the camera interact makes a big difference to the way it operates. "Electronic manual focusing systems usually have a slight lag between the focus ring being rotated and the focus adjustment being made," explains Ram. "If you're a filmmaker, the last thing you want to happen when you're manually focusing is to go past the subject, then have to rotate the ring in the opposite direction to bring the image back into focus. That's not pleasing to the eye when you're seeing that in video. With the communication system on the RF mount, however, manual focusing adjustments are far more precise. It's as close as you will get to having a mechanically focusing lens."
A hand on a Canon RF 50mm F1.2L USM lens attached to a Canon EOS R5.
A customisable lens control ring on Canon's RF lenses provides direct access to camera settings, offering a manual feel with heightened control. © Ivan D'Antonio

4. Improved handling

RF lenses feature a dedicated control ring that can be customised with a range of camera controls, including aperture, ISO and exposure compensation. It provides an accurate way to adjust the key camera settings without having to take your eye from the viewfinder.

"You've got people who are coming to the EOS R System from the video side, and you've got the people who are coming to it from the photography side," says Ram. "The cameras and lenses have been designed so that they can be customised according to the individual's needs. For instance, guerrilla filmmakers may want to have the RF lens control ring assigned to either ISO or exposure compensation. That way, if they're moving between locations of varying light, they are able to control the exposure in the same way they would with a variable ND filter."

Also, when zooming, the 1/8-stop aperture adjustment and zero fluctuation eliminates exposure shift and makes it possible to alter the exposure with the aperture without the rapid changes in brightness that occur with every other non-cinema lens.

A hand on a Canon RF 50mm F1.2L USM lens attached to a Canon EOS R5.
The Canon RF 28-70mm F2L USM lens combines four classic prime lenses – a 28mm f/2, a 35mm f/2, a 50mm f/2 and a 70mm f/2 – in a single zoom, saving you weight, money and the time it would take to change lenses.

5. Unique high-performance lenses

The combination of large diameter, short flange distance and upgraded communication has made it possible to create new kinds of lens designs. "Everyone at Canon is hugely excited about the possibilities," reveals Ram. "The Canon RF 28-70mm F2L USM lens is testament to that."

Capable of capturing incredibly sharp footage and equipped with a fast, constant maximum aperture, this high-performance RF lens is essentially four classic primes in a single zoom. "If you're a single shooter, you don't necessarily want to run around with a multitude of lenses and this one RF zoom can be used for almost all your requirements," says Ram.

"I think that the trinity of professional f/2.8 L-series zooms – the Canon RF 15-35mm F2.8L IS USM, Canon RF 24-70mm F2.8L IS USM and Canon RF 70-200mm F2.8L IS USM – make a great starting point for most filmmakers. The Canon RF 70-200mm F2.8L IS USM lens is probably my favourite of the trio. Compared to the Canon EF 70-200mm f/2.8 lenses, the RF version has considerably reduced focus breathing, and the result is beautiful.

"There are some filmmakers who'll want imperfections in their image quality to add character, and they will tend to gravitate towards using old-school legacy glass or really old vintage lenses. But we find that the majority of people want to have a really crisp, high-quality image for their videos, especially in order to make the most of the 8K capability of the Canon EOS R5. The RF lenses will definitely realise that level of resolution."

A mountain biker mid-stunt and upside down, silhouetted against the sky and framed by trees.
All three EOS R adapters work seamlessly with EF and EF-S lenses, so filmmakers have access to an impressive range of glass to help them achieve their desired aesthetic. © Ivan D'Antonio

6. Something old, something new

Although you need an RF lens to take full advantage of the RF mount's capabilities, you can continue to use your EF and EF-S lenses on a Canon EOS R System camera thanks to a selection of mount adapters. In addition to the standard Mount Adapter EF-EOS, the Control Ring Mount Adapter EF-EOS R enables you to get even more from your older lenses via the adapter's customisable control ring.

The Drop-In Filter Mount Adapter EF-EOS R has perhaps the greatest appeal for filmmakers, as it adds the ability to use drop-in filters. It's available with either a circular polarising filter or a variable neutral density filter, with the latter giving the precise control over exposure that's typically required when moving between indoor and outdoor locations. A clear filter is also available when you don't require any filter effects.

Napisal Marcus Hawkins

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