Full-frame vs Super 35mm: which sensor size should filmmakers choose?

The Canon Cinema EOS range features full-frame cameras and Super 35mm cameras, and an extensive line-up of cinematic lenses to suit each sensor format. But what are the main points of difference between Super 35mm and full-frame, and when would you choose one type of sensor over the other?

The big difference between full-frame and Super 35mm sensors is their physical size. This has implications for the field of view, your choice of focal length and creative control over depth of field, among other things.

Director of Photography Ian Murray says he continues to jump between full-frame and Super 35mm for his work. "It's a creative choice, because there are times when each is appropriate," he explains.

Ian has worked on campaigns for major brands, including Amazon, Volkswagen and Nespresso, and suggests that some subjects suit the larger depth of field that's easier to achieve on the smaller format. "I did a job involving food and shot it on Super 35mm. If the depth of field falls off too quickly with food, it doesn't look right. So I knew full-frame wasn't the best choice here.

"If you're shooting a period piece or something that needs to feel more retro, then Super 35mm is a better sensor size as that gives more of a classic, early cinema look," he continues. "If you're working on something in a run-and-gun style and it's more narrative-led – particularly when you want to be immersed in a character's world – then I think full-frame is a better choice."

• Super 35mm vs full-frame crop factor
• Creative depth of field control
• Lens compatibility
• Camera size and weight
• Resolution, dynamic range and low-light performance

In a stills camera, the sensor might be full-frame or APS-C. The latter is smaller and, as a result, APS-C cameras capture a smaller area of a full-frame lens's field of view, with a "crop factor" of 1.6x. The other way to look at this is that the subject is that much larger in the frame, so the APS-C sensor in effect increases the reach of the lens. For this reason, the crop factor is also known as the focal length multiplier. This means that the effective focal length of a 50mm lens, for example, becomes 80mm (50 x 1.6). It's the same with video cameras. Compared to the larger full-frame format, Super 35mm format has a focal length multiplier of 1.460x to 1.534x (depending on the aspect ratio).

All things being equal, the larger full-frame format gives a more expansive image than a Super 35mm sensor. To put it the other way around, full-frame requires a longer focal length to achieve the same angle of view as Super 35mm. The difference between the two sensor types' active area (approximately 1.5x) means that a 50mm lens on a Super 35mm camera gives a field of view that's similar to 75mm on a full-frame camera.

A common misconception when it comes to full-frame versus Super 35mm is that the larger full-frame sensor has an inherently shallower depth of field. But this isn't really the case. Attach a 24mm lens to a full-frame camera or a Super 35mm camera, and the depth of field will essentially look identical – it's just that the Super 35mm image will be less expansive. Full-frame does make it easier to achieve a shallow depth of field, though. In order to get the same view as the smaller Super 35mm format, you need to use a longer focal length or move the camera closer – both of which help to isolate the subject.

A shallow depth of field can be used to draw attention to the most important element of a shot, although the deeper depth of field that can be realised with Super 35mm has creative advantages too.

"If you want to be able to direct the viewer's eye without completely designing the scene, then you can do that very easily with a narrow depth of field," Ian explains. "There's also an argument to use full-frame on a story with a strong psychological element, as it can help you to pull the viewer inside a person's world if everything else around them is softer.

"I like to experiment with Super 35mm to get a slightly deeper focus, though," he continues. "Everyone seems to be going for that full-frame narrow depth of field look at the moment, but if you shoot Super 35mm at T2.8 or T4, or even T5.6, then you get a different presentation to everything you're used to seeing now. You need to have more control of your scene and be able to art direct the colours and throw light in there to guide the viewer's eye, though, as you won't be able to rely on selective focusing to do that for you. But then you get a completely different look and something that feels like the deep focus technique pioneered by [Citizen Kane cinematographer] Gregg Toland."

Full-frame lenses project an image that covers the active areas of both full-frame and Super 35mm sensors. It might appear wasteful to pair a full-frame lens with a Super 35mm sensor because the smaller format ignores a large part of the projected image. But doing so has a number of advantages. It allows you to use the sharpest and brightest area at the centre of the lens, for example, and it also gives you the flexibility to move between full-frame and Super 35mm cameras using the same lens.

Full-frame lenses tend to be heavier and slower (smaller aperture) than the equivalent Super 35mm lenses, though, which can be a consideration in some situations.

Using a Canon Mount Adapter EF-EOS R 0.71x, it's possible to maintain the original angle of view of a full-frame EF lens when it's mounted on a camera with an RF mount, particularly the Super 35mm Canon EOS C70. The adapter effectively shrinks the image from the lens by x0.71, and it also increases the light transmission to give an image that's 1-stop brighter.

Bigger sensor formats typically require bigger camera bodies. Stills cameras with APS-C sensors are usually significantly more compact than full-frame cameras. But the difference between full-frame versus Super 35mm video cameras is not as pronounced in this regard. In fact, the sensor size makes little difference in the Cinema EOS line. The Super 35mm EOS C300 Mark III and full-frame EOS C500 Mark II, for example, are practically identical in size and weight.

The EOS R5 C has really changed the game, though. The smallest camera in the current Cinema EOS range, it can capture 8K DCI RAW video across the full width of its full-frame sensor – but it's smaller and lighter than compact Super 35mm cameras such as the EOS C70 and the EOS C100 Mark II.

The larger area of a full-frame sensor can hold more photosites for a higher resolution or larger photosites for better sensitivity and improved low-light performance.

A higher resolution provides more flexibility, both in-camera and in post-production. Take the Canon EOS C500 Mark II with its 5.9K full-frame sensor, for example. If you set the camera to XF-AVC recording, you're able to take advantage of 5.9K over-sampling processing to record 4K DCI and 4K UHD footage with improved clarity, suppressed moiré and reduced noise compared with standard 4K content.

Switch to 5.9K RAW recording, and you can use the extra resolution during the edit to punch in, reframe a shot or apply image stabilisation while maintaining a 4K or Full HD frame. The EOS R5 C's full-frame 8K sensor offers even more scope in this regard. The potential downside to all this extra information is the increased amount of data that needs to be managed and stored, although the development of Cinema RAW Light has alleviated this problem.

Full-frame offers the potential for capturing a greater dynamic range, but the evolution of Super 35mm sensor technology in the EOS C300 Mark III and EOS C70 provides a new level of performance. The 4K Super 35mm Dual Gain Output (DGO) sensor in these cameras enables a wider dynamic range of 16+ stops to be captured in Canon Log 2, as well as delivering a low-noise low-light capability of up to ISO 102,400.

As Ian puts it, "Super 35mm is not going anywhere." Films have been shot on a format similar to Super 35mm since the 1950s, and filmmakers continue to be drawn to this standard when inspired by the look of classic films of the past.

In short, each format has its own characteristics, which may suit a particular project. Super 35mm remains a popular standard for good reason, and switching to full-frame is a creative choice, not a technical necessity.