EOS R System questions answered: all about Canon's full-frame mirrorless range

The EOS R System, Canon's groundbreaking full-frame mirrorless camera system, opens up new creative possibilities for photographers and filmmakers. At its heart is the innovative RF Mount, enabling a range of pioneering new RF lenses, including the acclaimed RF 28-70mm F2L USM zoom and innovative RF 600mm F11 IS STM and RF 800mm F11 IS STM prime lenses.

The EOS R, Canon's first full-frame mirrorless camera, was revolutionary for photographers and filmmakers. This was joined by the Canon EOS RP, which puts the power of full-frame mirrorless into a small, lightweight body, ideal for amateur photographers who are ready to take their photography to the next level, and the specialist Canon EOS Ra for astrophotographers.

The newest additions to the Canon EOS R System range take full-frame mirrorless photography and filmmaking to the next level. The Canon EOS R6 is a hybrid camera capable of capturing incredible images and 4K video in low light, while the flagship EOS R5 combines 45MP high-resolution stills and future-proof 8K movie recording.

So is one of these outstanding cameras right for you? Does the EOS R System offer better image quality than a DSLR? Can you use your existing lenses and accessories? We put 12 frequently asked questions to Canon Europe Professional Imaging Product Specialist Mike Burnhill.

1. What is a full-frame camera, and what advantages does full-frame offer?
2. What is a mirrorless camera, and what advantages does mirrorless offer?
3. When looking at the EOS R6's low-light performance, what does -6.5EV mean?
4. Does the EOS R System offer better image quality than a DSLR?
5. Should I buy an EOS R System camera or a DSLR?
6. Can I use my existing lenses, flashes and accessories with EOS R System cameras?
7. Are there limitations to shooting video?
8. What's the point of shooting 8K video with the EOS R5 when hardly anyone has an 8K TV?
9. Why did you add the multi-function touch bar to the EOS R and remove the AF joystick?
10. Why aren't there two card slots, or a higher frame rate, or in-body image stabilisation in the EOS R?
11. So why is in-body image stabilisation included in the EOS R5 and EOS R6?
12. What are the key differences between the cameras in the EOS R System range?

2. What is a mirrorless camera, and what advantages does mirrorless offer?

"When we talk about mirrorless in this context, we mean an interchangeable lens camera which doesn't use a single-lens reflex mechanism (mirror), but instead an electronic viewfinder (EVF). The biggest advantages come from the fact that eliminating the mirror removes certain restrictions in lens design.

"Because you have a mirror in a DSLR, which has to have room to flip up out of the way when you take a picture, you basically have to work around that mirror system when you design a lens. If you want to make a 21mm lens, the centre point of the lens should be 21mm from the sensor. But if you have a 40mm mirror in the way, the lens can't be 21mm away. Therefore you have to add extra elements to move all the optics forward, and more glass to alter the focus point, and lenses become much more complex pieces of engineering. If you eliminate the mirror, you've got potentially much simpler lens design, so you can concentrate on image quality instead of constantly having to fight around the design issues such as retrofocus.

"In fact, when Canon developed the EOS R System, we didn't start with the decision to build a mirrorless camera. We began by asking 'What's the future of lens design? Where do we want to go with lenses?' The impetus was 'reimagining optical excellence', which led to the internal codename Project R, and that's how it comes to be named EOS R."

"كان القرار الرئيسي هو تطوير حامل عدسة RF الذي يعد جزءًا جوهريًا من نظام EOS R. ويتميز بحلق عريض مشابه لحامل عدسة EF ومسافة حافة أقصر من الحامل إلى المستشعر حتى نتمكن من تصميم عدسات جديدة رائدة تعمل على مسافة مثالية من المستشعر. وهذا يتيح إنشاء بصريات أسرع وأكثر سطوعًا وأعلى جودة مع أداء مواكب للتطور المستقبلي. ويتضمن حامل العدسة RF أيضًا وصلة مبتكرة مكونة من 12 سنًا تتيح اتصالاً أسرع للغاية بين العدسة والهيكل، فضلاً عن أنه يوفر ميزة التوسع لاحقًا. تتمثل إحدى نتائج هذا التصميم في أن كاميرات نظام EOS R (باستثناء EOS RP) تتمتع بتركيز بؤري تلقائي فائق السرعة للغاية مع الكاميرات الكاملة الإطار غير المزودة بمرآة، بالإضافة إلى العدسات القابلة للتبديل وميزة تحسين العدسات الرقمية في الوقت الفعلي الفعالة للغاية.

"التخلص من المرآة يوفر ميزة أخرى، وهي أن يكون هيكل الكاميرا أصغر حجمًا وأخف وزنًا. إذ إنه مع تضمين البطارية وبطاقة الذاكرة، تزن كاميرا EOS R ‏660 جم ويبلغ وزن كاميرا EOS RP 485 جم فقط - وهذا أقل بكثير من كاميرات DSLR الكاملة الإطار المماثلة مثل كاميرا EOS 5D Mark IV من Canon التي تزن حوالى 800 جم. وبالطبع توجد كاميرات أخف وزنًا - تزن كاميرا EOS M من Canon المدمجة غير المزودة بمرآة أقل من 300 جرام على سبيل المثال - لكن في حالة الكاميرا EOS R لم يكن هدفنا هو تصميم الكاميرا الأخف وزنًا. لقد اتخذنا قرارًا بإنشاء هياكل EOS R وEOS R5 باستخدام سبائك المغنيسيوم القوية مع الاستناد إلى معايير إحكام قياسية احترافية لمقاومة الأتربة والمياه؛ لأن الموثوقية والمتانة مهمان للمصورين الذين صممنا كاميرات EOS R وEOS R5 من أجلهم.

"هناك بعض المزايا التقنية للتصميم من دون مرآة، مثل التخلص من الاهتزاز الناجم عن "تحريك المرآة"، لكن من المرجح أن يكون هذا الأمر مصدر قلق فقط في بعض الظروف المحددة للغاية. وبصفة عامة، فإن التخلص من المرآة الميكانيكية يعني أن نظام EOS R يمكنه التصوير في وضع صامت تمامًا، وهذا يعني أنه يمكنك التصوير في هدوء تام في كل أنواع الأماكن، بداية من حفلات الزفاف وصولاً إلى تصوير الحياة البرية. ويتيح استخدام محدد المناظر الإلكتروني أيضًا إمكانية معاينة الصور مباشرةً مع تطبيق إعدادات التصوير المفضلة لديك، فضلاً عن رؤية الصور التي تلتقطها في ظروف الإضاءة المنخفضة التي كانت تُعد عائقًا في الماضي".

3. When looking at the EOS R6's low-light performance, what does -6.5EV mean?

"The Canon Dual Pixel CMOS AF technology used in EOS R System cameras provides high-performance focus tracking in still photos and movies. It results in fast, accurate autofocus even in the kind of low-light conditions it was previously too dark to focus in. In one-shot mode, with a Canon RF 50mm F1.2L USM lens, the AF is effective down to -6.5EV on the EOS R6, -6EV on the EOS R5 and EOS R, or -5EV on the EOS RP.

"To give you an idea of how dark that is: imagine you're out in some remote area at night, where there are no street lights and the only light is a quarter-moon. That's about the same brightness as -6.5EV. The EOS R6 will focus in those conditions, as long as there's some contrast. No camera will focus with zero contrast – if you point it at a white wall, no matter how bright it is, it won't focus, because there's nothing to measure between."

4. Does the EOS R System offer better image quality than a DSLR?

"It partly depends how you measure 'better'. On an EOS R the RF 50mm F1.2L USM lens captures a sharper image than the EF equivalent, the EF 50mm f/1.2L USM – but you might prefer a softer look for some portraits, for example. That said, by most criteria the EOS R System sets a new standard in full-frame image quality. The Dual Pixel CMOS AF sensor delivers a perfect balance of rich, sharp detail and incredibly reliable low-light performance, and because almost every pixel in the sensor (100% vertically and 88% horizontally) is used for both imaging and autofocus, it ensures outstanding sharpness right across the frame.

"The Dual Pixel CMOS AF II introduced in the EOS R5 and EOS R6 goes even wider, covering 100% of the sensor in Face+Tracking and Auto Selection modes. The DIGIC X processor in these cameras enables us to use deep-learning artificial intelligence that recognises and tracks people's faces and eyes. It can identify a person's head even if they're wearing a mask and a helmet. The system also works with members of the cat and dog families, as well as birds to some extent.

5. Should I buy an EOS R System camera or a DSLR?

6. Can I use my existing lenses, flashes and accessories with EOS R System cameras?

"Although it's revolutionary in many ways, the EOS R System builds on Canon's 30-year EOS heritage. We retained the name 'EOS' for a reason – the EOS R System cameras are still part of the EOS family, with the compatibility that includes. We recognise that many photographers and filmmakers will have a substantial investment in EF and EF-S lenses, and you can use these lenses on EOS R System cameras with absolutely no loss of quality or functionality, using a choice of EF-EOS R mount adapters.

"With the standard Mount Adapter EF-EOS R you can use your EF and EF-S lenses on EOS R cameras seamlessly. With EF-S lenses, which are designed for EOS DSLRs with the smaller APS-C sensor, you'll get cropped images that match the smaller image circle of EF-S optics.

"The Control Ring Mount Adapter EF-EOS R adds a lens control ring, which is easy to use without taking the camera from your eye. This offers tactile manual control over various settings, just as you get on the RF lenses – you can customise it to adjust aperture, shutter speed, ISO sensitivity or exposure compensation, as you prefer – so in this sense it gives you the potential to get even more out of your existing lenses.

"Alternatively, the Drop-In Filter Mount Adapter EF-EOS R adds the ability to use drop-in filters, removing the need to fit filters on the front of a lens, which is especially useful for wide-angles with a large front lens element. It’s available with either a variable neutral density filter or a circular polarising filter."

"Whichever of these adapters you choose, your EF and EF-S lenses are fully compatible. There are technically a few that are not fully compatible – with the Canon 35-80mm Power Zoom lens, which was available in around 1990 for about a year, the lens will autofocus and exposure is all the same, but the power zoom won't work; and with Super telephoto lenses before 2010, the focus lock button does not work but everything else operates as expected.

"As for accessories, because the EOS R has different dimensions from other EOS cameras, it has its own model-specific Battery Grip BG-E22 for extended shoots. The EOS R5 and EOS R6 are both compatible with Battery Grip BG-R10, which features a multi-controller joystick for selecting the AF point when the camera is held vertically. But all EOS R System cameras are part of the EOS family, so your Speedlites will all fit, and you can attach them to standard tripods and so on.

"The EOS R5 and EOS R6 also use a new higher-capacity LP-E6NH battery, which gives a battery life of approximately 490 shots on the EOS R5 and 510 shots on the EOS R6 (in LCD power-saving mode in both cases). This is backwards-compatible too, so it can be used in every camera that's powered by the LP-E6 lithium-ion type of battery since it was introduced in 2008, including the EOS R, the EOS 5D Mark IV and EOS 6D Mark II. You can also use older LP-E6 batteries in the EOS R, EOS R5 and EOS R6, although you will get slightly less power.

"The more compact EOS RP uses the same LP-E17 battery as the Canon EOS 750D and Canon EOS 200D."

8. What's the point of shooting 8K video with the EOS R5 when hardly anyone has an 8K TV?

"Recording in 8K gives you more options when it comes to editing. You can shoot wide with 8K and then punch in with a tighter crop or pan or zoom and still retain a 4K resolution image, which is probably as high as most people need at this moment in time.

"If you only need Full HD output, you're effectively giving yourself the option of using a 16x zoom in the edit. Because you're zooming into 8K worth of data, you get this amazingly natural zoom without any of the negative effects you'd get from using such a long zoom lens. It looks as if you've used a super-high quality Cinema parfocal zoom lens, with no breathing, no change in magnification and no change in exposure. This is like the best quality zoom you've ever seen.

"You also have a 4K HQ mode on the EOS R5, which oversamples the video from 8K to give the most detailed 4K image possible. If you record natively in 4K then you're actually only recording 25% of the data in both the red and blue channels due to the Bayer filter array on the sensor. The missing data can cause moiré and introduce artefacts, as well as softening the image.

"With 8K, though, you get 4K worth of red data and 4K worth of blue data, and together that gives you a much higher quality 4K signal. It's theoretically the maximum 4K signal you can get, so therefore sharpness and colour are massively improved and noise is reduced. And it's all saved at the same file size as standard 4K."

9. Why did you add the multi-function touch bar to the EOS R and remove the AF joystick?

"Designing a whole new camera gives us the opportunity to try different ideas. Some people love the multi-function touch bar on the EOS R, which you can customise to control functions such as AF or ISO setting or white balance. It’s similar to the familiar EOS control wheel, but with the added benefit of silent operation and enhanced weatherproofing. But we're aware that some people really don't like it. Other innovations like the customisable control ring have been pretty universally well received. So has the touchscreen AF system, which really gives you much better control than a joystick – can you imagine trying to use a joystick to select between 5,655 AF points, as you can on EOS R (or 4,779, as on EOS RP)?

"It's about offering the best usability we can for the features available. We tried to balance the new features and functions with familiar EOS handling, menus and so on, so you don't need to grasp a whole new system and can get up and running as quickly as possible. We won't always get the balance right, and we always welcome feedback.

"In fact, feedback from users is one of the reasons that the joystick is included on the EOS R6. The joystick is also featured on the EOS R5, but it was always part of this camera's design. It's a 5-series body, so we knew it was going to appeal to Canon EOS 5D Mark IV users, who are familiar with the joystick."

10. Why aren't there two card slots, or a higher frame rate, or in-body image stabilisation in the EOS R?

"We totally understand why professionals value dual card slots. The Canon EOS-1D Mark II was the first camera with dual card slots. We know some people find it important for backup, or a more flexible workflow, or simply a feeling of security just in case. In the EOS R t was a balance, for the target market. When we design cameras, we tend to be looking at who the customer is for that product, and what they want. That's our starting point. So we'll put some features in and leave some features out, based on what we feel the customer requires, rather than trying to cram everything in.

"The problem with the EOS R, really, is that it's got such a good feature set, it's appealing to people who are more advanced than the users it's actually aimed at. Professional wedding photographers, for example, want to use it for their work, because it's so compact, offers silent shooting, and so on. And it's great for that. But the EOS R is designed for the photography enthusiast, and it doesn't offer everything you'd find in a top-of-the-line professional camera.

"When it comes to in-body image stabilisation, the EOS R System does have tech built in like 5-axis Digital Movie IS, and the EOS RP offers a powerful Dual Sensing IS system that reduces camera shake for handheld photography."

11. So why is in-body image stabilisation included in the EOS R5 and EOS R6?

"The two types of image stabilisation are more effective with different types of lenses. So, in-body IS is better for wide-angle work, and lens-based IS is better for telephoto work. But the magic trick is combining the two systems to give a better performance across a wider range of focal lengths. That's what we've been working on with the EOS R5 and EOS R6, because the in-body IS alone wouldn't have significantly improved the level of stabilisation already offered by an IS lens, but having them synchronise together allows us to boost the overall performance.

"We've designed the system to work in tandem with any stabilised RF or EF lens, but you get a noticeable improvement from the in-body system when using an RF lens thanks to the faster communication between the camera and lens. The degree of improvement depends on the lens. The RF 85mm F1.2L USM and the RF 28-70mm F2L USM have very big image circles, for example, which means the IS system has more room to move. Neither of these lenses has built-in IS, but you can get up to 8 stops of stabilisation when they're used on the EOS R5 or EOS R6.

"If you attach an RF lens with built-in IS to these cameras then you'll also get up to 8 stops of stabilisation, but because the body and the lens systems are working together, you will actually see more of an improvement in performance than indicated by the rating. We have to measure stabilisation according to the CIPA standard. But this is done on a machine, and it doesn't take into account the low-level vibrations that are generated when a person breathes or has a raised heart rate or gets arm ache. So in real-world use you're going see even more of an improvement in image quality, because our combined IS system is correcting for different types of vibration that may not be considered in the CIPA standard."

12. What are the key differences between the cameras in the EOS R System range?

"With its 45 megapixel resolution and full-width 8K RAW video recording, the EOS R5 is the flagship camera in the EOS R System range for obvious reasons. Along with the EOS R6, it introduces our next-generation DIGIC X processor, which is three times more powerful than the processor in the EOS R. DIGIC X increases our processing capabilities exponentially. Not only does it allow us to do 8K processing, it enables us to use the deep-learning AF system – to process the data from the sensor and match it to an on-board database.

"DIGIC X allows us to introduce a host of little improvements through the camera too. You can record video to one card and stills to the other card, for example, and rename folders in-camera. It also enables greater customisation options. One that I find particularly useful is setting AF Selection on the RF lens control ring. I've narrowed down my AF points to two modes – single point and automatic tracking – and I can switch between the two just by clicking the ring.

"The new processor also gives additional in-camera image processing functions. The EOS R5's Dual Pixel Raw option now features Portrait Relighting, which allows you to replicate the effect of using a reflector, and Background Clarity, which selectively boosts the contrast of the background in an image without affecting the subject.

"The EOS R6 sits between the EOS R5 and the EOS R. Although it has a lower resolution than the EOS R, its advanced AF system and high sensitivity expandable up to ISO 102,400 make it an even better choice for low-light work. It can shoot at 12fps using the mechanical shutter or 20fps using the electronic shutter, and it's better specified for video than the EOS R, including the ability to record full-frame 4K at 60p. The EOS R6 also has a better viewfinder, dual card slots and a joystick, so there's a whole host of upgrades over the EOS R.

"The Canon EOS R is designed for photography enthusiasts. The Canon EOS RP is a smaller, lighter camera aimed at advanced amateurs looking to take a step up to the full-frame mirrorless EOS R System. It is the lightest full-frame camera Canon has produced, making it ideal for travel, landscape and portrait photography and videography, or indeed any kind of creativity on the go.

"Some of the differences between the EOS RP and the EOS R are related to the EOS RP's smaller size. The vari-angle touchscreen is slightly larger on the EOS R, has a higher resolution, and offers a higher number of selectable AF points (although the 4,779 on the EOS RP is still phenomenal coverage compared to the rest of the industry). The EOS R's larger body means a larger battery and therefore greater battery life than the EOS RP.

"Other differences arise because the EOS R is designed for more ambitious users. So it has a sensor with more megapixels, and it supports advanced features such as High Frame Rate movies, 10-bit C-Log output via HDMI, and Dual Pixel RAW. The EOS RP also doesn't have the EOS R's multi-function touch bar or an OLED display panel on the top of the body; instead, the EOS RP has a more familiar mode dial.

"On the other hand, the EOS RP introduces some exciting features for the first time, such as focus bracketing, and Eye AF while continuous focusing in Servo AF mode (available for the EOS R with Firmware 1.20 update). It also offers slightly different Picture Styles and AF mode options.

"For more details, read our EOS R5 vs EOS R6 comparison article, or see the product pages for the EOS R5, EOS R6, EOS R and EOS RP, which include complete specifications and model comparisons."