Discover what makes Canon's Flex Zoom cinema lenses so special

Fast, flexible and with incredible image quality, the Flex Zoom lineup brings even more versatility to professional 4K and 8K HDR productions.
A woman holding a cup being filmed by a Canon Cinema EOS camera with a Canon Flex Zoom lens attached.

Canon's Flex Zooms deliver the same sharp, clean look as Canon's EF Cinema Primes, as well as the natural colours and beautiful skin tones that all of Canon's cinema lenses are renowned for.

Fast, flexible and offering sublime cinematic image quality, Canon's Flex Zoom cine lenses bring a superb level of performance to high-end film productions.

The Canon Flex Zoom series launched with two full-frame lenses in PL or EF mount – the CN-E20-50mm T2.4 L and CN-E45-135mm T2.4 L. The addition of two Super 35mm options completes the Flex Zoom lineup and brings that outstanding optical performance and flexibility to an even wider range of filmmakers.

"The Canon CN-E14-35MM T1.7 L S / SP and the CN-E31.5-95MM T1.7 L S / SP share many of the same features as their full-frame counterparts," explains Canon Europe Product Marketing Specialist Jack Adair. "The form factor is very similar, and they offer the same breathtaking image quality for 4K and 8K HDR productions, as well as the same advanced lens metadata support.

"The only notable differences are the focal lengths, maximum T-stop values and the fact that two of the Flex Zooms offer full-frame coverage and two offer Super 35mm coverage."

The modular design of the Flex Zooms means that not only can the mounts be switched between EF and PL by a Canon authorised service centre, but the lenses can also be converted from Super 35mm to full-frame and back again with a relay kit. The flexibility of these lenses means they really do live up to their name.

So, what are the key features of the Flex Zoom series, and how do these premium cinema lenses meet the needs of today's DoPs and cinematographers?

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Three actors – a Black man, an Asian woman and a white woman – are each seen in profile, all looking to their left.

1. Fastest cinema zoom lenses for their focal length

Canon's Flex Zoom lenses maintain a constant maximum T-stop value across the entire zoom range – a bright T1.7 with the Super 35mm Canon CN-E14-35MM T1.7 L S / SP and CN-E31.5-95MM T1.7 L S / SP, and T2.4 with the full-frame CN-E20-50mm T2.4 L and CN-E45-135mm T2.4 L. Both the Super 35mm and full-frame Flex Zooms are the fastest cinema zoom lenses in their class covering their focal lengths.

"Letting so much light into the lens means that the Flex Zooms offer excellent performance in low light,” says Jack. "Equally important, of course, is that these large T-stops give you an incredibly shallow depth of field to work with, enabling you to create powerful cinematic content whether you’re shooting in full-frame or Super 35mm."

Even with such a shallow depth of field, the focus fall-off is very smooth and all the Flex Zoom lenses are equipped with 11 iris blades, resulting in beautiful, rounded bokeh.

"Many of the old cinema lenses have a pronounced, angular bokeh, but the CN-E20-50mm T2.4 L feels like a mature and modern cinema lens, which makes it perfect for commercials," says DoP Ian Murray, who tested the full-frame Flex Zoom on a short film (above). “Behind the actress was round, smooth bokeh, while the large format's fall-off meant she was beautifully isolated from the background."

A Canon Cinema EOS camera with a Flex Zoom lens attached on a table in a Western-style bar.

With their fast maximum T-stop and 11-bladed iris, all the lenses in the Canon Flex Zoom series deliver beautifully cinematic images. "There's also smooth focus roll-off, virtually no focus breathing and excellent parfocal performance," adds Jack. © Ember Films

A man holding a Canon Cinema EOS camera with a Flex Zoom lens attached films a woman holding a cup in her hands.

"Unlike many modern full-frame lenses, that are just very clean and completely without character, the Canon CN-E20-50mm T2.4 L has a refinement and a richness to it," says DoP Ian Murray.

2. Uncompromising image quality

Canon's Flex Zooms deliver a detailed, refined image throughout their focal length range and display image quality characteristics that are consistent with other primes and zooms in the Canon cine lenses range, explains Jack.

"All four Flex Zooms provide crisp, clear imagery with warm skin tones and beautiful colour reproduction," he says. "The clean look is wonderful for high-end cinema and documentaries. Many people like a certain look with a lens, but one of the benefits of the Flex Zooms is that you're starting with a clear base that you can tune using third-party filters."

DoP Jonathan Jones appreciated the image quality afforded by the Flex Zooms while filming a movie trailer (below) using a Canon EOS C500 Mark II paired with Canon CN-E20-50mm T2.4 L and CN-E45-135mm T2.4 L lenses.

"These lenses are clean, classic and controlled in terms of flare," says Jonathan. "If you want it to flare and you bring the light in, they flare beautifully."

Jonathan kept the lighting simple to avoid his film looking over-stylised. "We were looking for texture, and you need the best equipment to capture that," he continues. "The Flex Zooms are so fast, and the look is clean and natural, not overly 'digital' or clinical."

3. Versatile zoom range

Each Flex Zoom lens pairing provides the focal length coverage to satisfy a wide range of productions. The full-frame Flex Zooms have a combined zoom range of 20-135mm, while the Super 35mm Flex Zooms combined offer a useful range of 14-95mm.
As Jonathan highlights, having a lens that offers the flexibility of broad focal length coverage without compromising optical quality paid off while he was shooting his movie trailer.

"I used zooms due to the setup and the speed at which we shot," he says. "To do what we did in two days, we had the timing down to five-minute intervals. It's that tight. You couldn't add lens changes into that. I might be on the dolly and say, 'Let's look at a 50mm. No, let's go 85mm'. Within a second, you're there with the zoom. Optically, they are so close to primes you would struggle to notice the difference."

A filmmaker stands behind a Canon Cinema EOS camera with a Canon Flex Zoom lens attached.

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A close-up of a Canon Flex Zoom lens being attached to the body of a camera.

"The Flex Zooms are available in EF or PL mount, enabling them to be mounted on Cinema EOS or third-party cameras," explains Jack.

A side profile of a Canon CN-E14-35mm T1.7 L S / SP lens.

The ability to switch from PL to EF mount and from Super 35mm to full-frame via the relay kit gives filmmakers maximum flexibility.

4. Mount flexibility

As the name suggests, Canon's Flex Zoom lenses are a flexible solution for high-end film productions. All four lenses are available to purchase or rent in either PL or EF mount, and further flexibility is afforded by allowing for the mounts to be interchanged as and when the production requires. This paid-for service is available via Canon authorised service centres or authorised third-party companies.

The Flex Zooms can also be switched from Super 35mm to full-frame and vice versa. Using the relevant relay kit, Canon authorised service centres can change the front element, focus and iris rings on the CN-E14-35MM T1.7 L S / SP and CN-E31.5-95MM T1.7 L S / SP so that the lens projects a full-frame image circle. The CN-E20-50mm T2.4 L and CN-E45-135mm T2.4 L can also be converted to give a Super 35mm image circle.

A Canon CN-E45-135mm T2.4 L Flex Zoom lens with a hood attached.

Each of the Flex Zoom lenses has a 112mm filter thread which enables you to use screw-in third-party filters to enhance the image or to protect the front element. © Ember Films

A finger holds back the rubber cover on the rear of a Canon Flex Zoom lens to show how the flange back is adjusted.

Another shared feature is the adjustable flange back for fine-tuning front and back focus. This adjustment can be made using a flathead screwdriver via a rubber cover on the rear of the lens.

5. Robust design and construction

Built to meet the demands of high-end cinema productions, Canon Flex Zooms are compact but manufactured with metal parts for durability.

"The quality of these lenses is phenomenal," says Jack. "Not only are they rugged enough to be used in all kinds of environments, but they also offer quick and precise operation. The Flex Zoom range has a consistent front diameter, and industry-standard gear positions and gear rotation angles across all the lenses, so they can easily be paired with third-party follow focus accessories and lens supports.

“This consistent and unified design ensures operators have one less thing to worry about on set: they can remain productive, work quickly and efficiently, and focus on the production."

A cameraman films two men brawling on a table in a Western-style bar on a Canon Cinema EOS camera with a Canon Flex Zoom lens.

"The Canon Flex Zooms will be used predominantly in drama, movies and commercials – the high end of the spectrum," says Jonathan. "You could use them for literally anything, but really it's going to be aspirational productions." © Ember Films

6. Advanced lens data communication

As they comply with common communication standards, the Canon Flex Zooms can be deployed in a virtual production environment.

"All four lenses support Cooke /i Technology and Zeiss eXtended Data protocols on PL mounts," explains Jack. "They also have a Lemo 4-pin connector that enables metadata support for cameras that aren't compliant with these protocols. This gives the lens positional information that can be fed into virtual systems, ensuring that when the camera and lens is panning, tilting and zooming, the virtual background is also adjusting to render a natural image."

The EF mount enables the communication of Canon metadata, allowing users to take advantage of advanced camera functions when shooting with a compatible Cinema EOS camera – including Dual Pixel Focus Guide for greater accuracy when manually focus pulling.

Completing the Flex Zoom lineup to offer both full-frame and Super 35mm options means Canon has delivered a versatile lens range for modern filmmakers who want superb cinematic image quality on high-end and premium productions.

Marcus Hawkins

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