Canon full frame mirrorless cameras
After the detailed review of full frame mirrorless cameras of the rival Nikon, I’ll now do in this article the review of Canon full frame mirrorless cameras. Within the EOS R system is Canon’s new RF optical mount, combining mechanical and electronic optical engineering. And these Canon RF lenses are simply spectacular… We have already seen it in detail in the dedicated article about Canon RF lenses. By the way, I detailed there all interchangeable lenses (Canon and third-party brands) that would fit on any body presented in this article. Even if the choice is quite limited for now (at the time I write this article), you’ll found several zoom or prime lenses from Canon and I’m pretty sure, Canon will work hard to produce new lenses soon.
The end of summer 2018 marks the long-awaited arrival of Canon in the full-frame mirrorless market. Firstly, the release of the Canon EOS R in September 2018, followed a few months later by the Canon EOS RP, in February 2019. These two cameras are positioned somewhere between the amateur range for the RP and the expert range for the R. In December of the same year, Canon released the EOS Ra, a very specific camera designed for astrophotography.
The following year, Canon moves into the higher category with the arrival on the market of the EOS R6 and EOS R5 in August 2020, which are more considered as semi-pro. Canon makes no secret of the fact that they clearly echo the DSLR 6D series, even the 7D Mark II for the EOS R6, and the mythical saga of 5D for the EOS R5. Finally, in October 2021, Canon announces the arrival of the new Canon R3, the very top-of-the-line mirrorless camera! In November 2022, Canon released the second version of its famous full frame camera (Canon R6), the Canon R6 II.
Worth noting that all the lenses of the EF and EF-S range for DSLR are compatible with the EOS R cameras thanks to an adapter ring. With the new Canon lenses (RF), you will be able to use the whole Canon optical park, even if I would globally advise, if you choose a Canon full frame mirrorless camera, to stay on the ones dedicated to the RF mount.
All of this is enough to make our mouths water! Let’s now have a closer look at the main technical features of each of these cameras. At the end of the article, I will try to guide you to choose one of these cameras according to your photographic and video needs, but also to your budget. If you have a smaller budget and want a lighter/smaller camera, don’t hesitate to look for a Canon APS-C mirrorless (EF-M mount).
Unfortunately (if you can say!), in June 2022, Canon decided to release their first APS-C Canon cameras using the RF mount, the same as Canon’s full frame mirrorless cameras. I break down their cameras and would include in the future any others that Canon may release. This probably puts an end to the EF-M mount and the interest in choosing these APS-C mirrorless instead of those using the Canon RF mount.
If you’re interested in what other brands have to offer, you can check out all Sony mirrorless cameras. We wrote a similar comprehensive guide to help you in your choices!
01/17/2023
- Addition of the brand new canon mirrorless camera lineup, the Canon R6 Mark II and all the main specs to know,
01/20/2023
- Addition of the video-oriented Canon Full frame mirrorless camera, the Canon R5C
If you are still hesitating about which camera to choose, I invite you to read our guide detailing all the elements to consider when buying a camera.

Check out my practical photography packs. It's a simple, fun and entertaining way to learn and improve in photography, especially in the field!
Canon mirrorless camera lineup
We finally published our full guide of the best curent Canon RF lenses for full frame mirrorless cameras. Don’t hesitate to check it out!
Canon Full frame cameras | Released date |
---|---|
Canon RP | October 2018 |
Canon R | October 2018 |
Canon R6 | July 2020 |
Canon R5 | July 2020 |
Canon R3 | September 2021 |
Canon R6 Mark II | November 2022 |
The table on the side shows the chronological release of Canon’s full-frame mirrorless cameras. Canon first released two entry-level bodies (Canon R and RP) in 2018. Two years later, Canon released two solid references, the Canon R5 and Canon R6, which were very successful and are still excellent choices for many people. The Canon full-frame R3 was the brand’s entry into the world of wildlife and sports photography, offering a professional camera equivalent to or better than the EOS-1D X Mark III DSLR. At the end of 2022, Canon decided to renew the Canon R6 with a slightly improved version.
Canon Full frame EOS R
The Canon EOS R was the first full frame mirrorless camera using the new RF mount. It is built around the same 30-megapixel Dual Pixel CMOS sensor as the 2016 EOS 5D Mark IV but designed for the new RF lens series. Among the main features: an ISO sensitivity that extends from 100 to 40,000iso (102,400 in extended), 5655 focusing points, bursts in raw up to 8fps, and 4K video at 25fps and Full HD at 60fps. Regarding connections, we find a USB-C input, an HDMI Mini Type C output, a mini-jack microphone input, a headphone jack and a remote control jack. However, there is only one memory card slot in SDXC format, UHS-II compatible, which is a format a little more popular than the XQD of Nikon Z6/Z7.
The 30MP sensor offers good dynamic range and low-light performance, coupled with the latest Digic 8 processor. Overall, autofocus performance is said to be impressive, even at the highest burst speeds. The single AF is fast, accurate and currently leads the market in low-light performance. The camera uses the C-RAW compressed format, which is in my opinion very useful (allowing to have raw files half as heavy!).
The possible burst at 8 Frames-per-second (fps) is not very impressive, and it is difficult to follow moving subjects when shooting in burst, which will certainly discourage sports or fast-moving subjects’ photographers.
When it comes to video, we may also be a little disappointed… Although the EOS R is capable of capturing 4K video with excellent color rendering, it carries an unfortunate 1.83x crop, making it difficult to shoot wide-angle footage. The lack of body stabilization further limits the camera’s utility as a video camera.
The EOS R may not have the most impressive spec sheet, but as a precursor to Canon’s new RF mount, it is still an important camera. With the EOS R, Canon offers a nice camera, pleasant to use and with convincing responsiveness and reliability. This full-frame mirrorless model will surely be positioned in the middle of the range, to seduce the amateur/passionate photographers. But considering the lacks and what the brand did skip, this camera is clearly not professionals oriented.
Canon mirrorless Full Frame EOS RP
The Canon EOS RP is one of the smallest and lightest full-frame cameras available on the market, as well as the cheapest full-frame camera ever launched. Even if its specificities won’t set the world on fire, it puts forward serious arguments: a 26.2-megapixel CMOS sensor, a Dual Pixel autofocus, an ISO sensitivity from 100 to 40,000 iso (extendable to 102,000 iso like the EOS R) thanks to the digic 8 processor, a large touch screen mounted on a spherical head… Relying on 4,779 AF points, the autofocus of the EOS RP proves to be precise and fast. The EOS RP is also able to detect the subject’s eyes and to track this last one, what will bring happiness to all portraitists.
However, the EOS RP is only able to capture 5 frames/second in single AF mode. This is far from some competing cameras, but the EOS R performance is also somewhat limited with these 8 fps. The two Canon mirrorless full frame cameras (Rp and R) are therefore not suitable for uses requiring a very high burst.
About video, the RP is comparable to its big brother, the R. Despite a 4K capture, quality is disappointing, with significant cropping and an autofocus considered quite poor.
The connections offered by the EOS RP is complete: two 3.5mm jacks (one for an external microphone, the other for headphones), a mini-HDMI jack and a USB type C port. The camera has a single slot for SDXC format memory card and UHS-II compatible.
As you can see, the RP is a nice little camera with a solid JPEG image quality, seducing by its reactivity, as much for powering up, as focusing and shooting. Only its low burst rate and mediocre video quality prevent it from reaching the level of the best full-frame mirrorless… but which are also sold (much) more expensive.
Canon Full frame EOS Ra camera
At the end of 2019, Canon offers a version of its EOS R camera which is optimized for astrophotography. It has exactly the same technical characteristics as the EOS R, but with two notable differences: a factory-modified full-frame IR filter/sensor (improved sensitivity) and a 30x magnification, instead of the 10x magnification, which places it in the very closed circle of astrophotography cameras.
The difficulty in astrophotography is the lack of light, but also the fact of matching the spectral sensitivity of the cameras with the radiation of celestial objects. It is precisely in this area of the near infrared that nebulae emit. A spectral range in which conventional cameras are not very sensitive, thus requiring an adapted system.
The EOS Ra is unique within this context, as the infrared (IR) filter layer on the sensor of the regular EOS R has been removed, which highlights the red tones that are often difficult to capture with ordinary cameras. Coupled with a reasonably large pixel size of 5.36 microns, this camera promises to capture a lot of light and to produce low noise at higher ISO sensitivities, on account of the sensor size combined with the 30MP sensor’s megapixel.
If you want to own a modified full frame mirrorless camera and prefer to have your warranty intact, this is the one you’re looking for.
Canon EOS R6 and R5 mirrorless Full frame cameras
With the arrival of the EOS R6 and R5, Canon do mark a real change from the previous RF mount cameras. They are the true successors to their mirror-image counterparts in the very popular EOS 5D and EOS 6D digital DSLRs.
The most obvious difference between these two digital-cameras is the resolution. The R5 is based on a new 45-megapixel sensor, which means it offers more than enough resolution for any task. As for the R6, the 20MP is not the most defined on the market, but it is sufficient in most cases and allows for lighter files. The Canon EOS R6 can reach a sensitivity of ISO 102,400 (expandable to ISO 204,800), where the EOS R5 caps at ISO 51,200.
These two bodies also have common technical features, such as the 5-axis stabilization of the sensor. There is also a burst at 12 fps (with mechanical shutter) or 20 fps (with electronic shutter), with real-time subject tracking. And both have 1053 AF points.
But the major innovation is the introduction of an internal stabilization system. Its arrival was long awaited, especially since the current cameras have increasingly impressive potential in the field of videos. This area is the other main difference between the two cameras: the R5 has the ability to shoot in 8K at 30p and 4K at 120p across the entire width of the sensor, while the R6 captures in 4K at 60p with a slight crop. Both cameras are equipped with headphone and microphone jacks.
As to battery life, the R5 is rated at 320 shots through the viewfinder and 490 on the LCD. The R6 shows slightly better results: 380 photos using the viewfinder in standard mode, and 510 via the LCD screen. Both cameras can be charged if you have a USB-C charger or power bank. They both have two memory card slots, with a difference for the R5 which has a specific slot for CF express.
Canon Full Frame R5C
Some time after the release of the R5, Canon released the R5C, a “Cinema” version of the R5, especially to answer the widespread criticism of overheating. So in order to reduce the problem, Canon has redesigned the body to become thicker and integrate a fan. If the photography part remains the same, same viewfinder, same AF, same burst rate etc. except for the sensor which loses stabilization, on the other hand, the video part is more “professional”, almost incomprehensible for someone who doesn’t do high level video intensively, so many options like 4K120p with sound, codecs and technologies are available.
However, AF in video mode is no longer as effective as in stills, unlike the R5. Recording may be unlimited but the battery does not last very long, a shame to replace a software limitation with an energy limitation.
And if, for the price, you probably have the most complete camera against the Sony A7S III and Panasonic S1H, especially with 8K, it is also the most expensive of the three Full frame cameras. Unless you have special needs in advanced video, there are much more interesting and affordable options.
Canon Full Frame R3
Three years after the first EOS R mirrorless’ arrival, Canon finally announces the EOS R3, a high-end mirrorless camera designed for sports, wildlife, and photojournalism. This Canon EOS R3 is a fusion between what’s best: the famous Full frame DSLR EOS-1D X Mark III and the EOS R5 and R6 cameras, all in a rugged, professional-level camera body, with weather sealing.
It’s a full frame 24MP camera built around the RF lens mount. This choice allows Canon to compromise between definition, acquisition speed and file weight, all while maintaining very good performance in high ISO. The sensitivity range extends from ISO 100 to 102,400, expandable to ISO 204,800. There is a sensor stabilized on 5 axes. Its new CMOS sensor allows a maximum shooting speed of 30 fps with AF and AE tracking. The camera is based on a total of 4779 AF points – it is quite a lot, but still less than the EOS R5 (5940 points) and the EOS R6 (6072).
The biggest new feature of the EOS R3 is the Eye Control, an eye-controllable autofocus. All you have to do is look at the subject in the electronic viewfinder, press the AF-On button (or press the shutter release halfway), and the camera will focus and track the subject. Compared to the EOS R5/R6, it also gains a new car and motorcycle detection and tracking mode. Not only that, the AF is also able to detect the rider’s head for an even better focus.
Regarding video, no 8K, but this EOS R3 offers 6K at 60 fps in Raw.
In terms of connectivity, the EOS R3 is quite complete: USB Type C 3.2 port, micro-HDMI port, and 2 jack 3.5 mm (microphone and headphones). It also includes an RJ45 port, intended for photojournalists. For storage, the camera has a slot for SDXC cards (UHS-II compatible) and another one for CF Express cards. The EOS R3 is compatible with 2.4 and 5 Ghz Wi-Fi and Bluetooth 5.0.
This is Canon’s most powerful hybrid camera so far, and it only begs to be tested in the field!
Canon Full frame R6 Mark II mirrorless camera
Early November 2022, Canon decided to renew its R6 Full frame, which had been a huge success. I must say that Canon had put all its energy into it, after the relatively average EOS R and Rp, Canon had reconsidered its copy and had done its best. So much so that this R6 II is not as different from the R6 as the R6 was from the R.
The first difference is the sensor, which is now at 24MP definition, matching the definition of most competing cameras such as the Nikon Z6 II, the Panasonic S5 II and the A7 III. Nevertheless, it does not benefit from the latest technologies such as backlighting that can be found in the competition or memory stacking found on the most high-end cameras. However, this sensor allows the R6 II to offer a 6K60p video recording without crop although you have to use an external recorder. The sensitivity of the sensor has not changed compared to the R6, despite the additional pixels, since it offers a native range of 100 to 102400 ISO.
Image stabilization remains as good and the mechanical burst rate is still 12 fps. However, in electronic shutter, the burst rate is increased from 20 to 40ips. But without a stacked sensor, this one remains easily subject to problems caused by the sensor’s reading speed such as distortions when following moving subjects sideways, banding in artificial lighting conditions and rolling shutter in video. The AF also remains effective and receives new subject detection, mainly trains and planes. The rear screen and EVF are the same as those of the R6, which were already what you would expect from a camera at this price.
Regarding autonomy and connectivity, the wifi gains the 5GHz band for increased speed and the camera can shoot 50% more photos with the LCD and 15-20% more with the EVF. A good improvement on this point, hybrid cameras being quite criticized on the autonomy, but it is still below what Sony is able to offer. Memory cards used are still a dual-slot from SD to UHS-II, rather limited for 6K (hence the interest to use an external recorder via HDMI port).
In short, a good update for the R6 but no revolution either, especially since its price has increased since it comes out at 2900€ which is 200€ more than the first version. But let’s not forget the inflation and the shortage which have caused a price increase on all camera gear from almost all brands.
Canon mirrorless cameras Full frame - Main features
After these nice speeches, here is a summary table with the essential characteristics to compare. You’ll found bellow all Canon mirrorless camera (Full frame), except the Canon R5C which I consider very specialized.
Features | ![]() | ![]() | ![]() | ![]() | ![]() | |
---|---|---|---|---|---|---|
Price | 999$ | 1499$ | 2499$ | 3899$ | 5999$ | 2899$ |
Released date | october 2018 | october 2018 | July 2020 | July 2020 | September 2021 | November 2022 |
Check prices | Amazon / B&H | Amazon / B&H | Amazon / B&H | Amazon / B&H | Amazon / B&H | Amazon / B&H |
Sensor Resolution | 26.2 MP | 30.4 MP | 20.1 MP | 45.0 MP | 24.0 MP | 24.0 MP |
Sensor Type | CMOS | CMOS | CMOS | CMOS | Stacked CMOS | CMOS |
Weight (with battery /card) | 485g | 660g | 680g | 737g | 1015g | 670g |
Dimensions (W×H×D) | 132.5 × 85.0 × 59.4 mm | 135.8 x 98.3 x 67.7 mm | 138 x 97.5 x 88.4 mm | 138 x 97.5 x 88 mm | 150 x 142.6 x 87.2 mm | 138,4 × 98,4 × 88,4 mm |
In-Body Image Stabilization | NO | NO | Yes | Yes | Yes | Yes |
Low-Pass Filter | Yes | Yes | Yes | Yes | Yes | Yes |
Battery Life (Viewfinder) | 250 images | 350 images | 380 images | 320 images | 620 images | 450 images |
Battery Life (Electronic mode) | 250 images | 350 images | 510 images | 490 images | 860 images | 760 images |
Battery | LP-E17 | LP-E6N | LP-E6NH | LP-E6NH | LP-E19 | LP-E6NH |
Image Processor | DIGIC 8 | DIGIC 8 | DIGIC X | DIGIC X | DIGIC X | DIGIC X |
Sensor Size | Full Frame | Full Frame | Full Frame | Full Frame | Full Frame | Full Frame |
External flash | NO (only via hot shoe) | NO (only via hot shoe) | NO (only via hot shoe) | NO (only via hot shoe) | NO (only via hot shoe) | NO (only via hot shoe) |
Flash Max. Sync Speed (Mechanical) | 1/180 | 1/200s | 1/250 | 1/200 | 1/250 | 1/180 |
Viewfinder Type & Resolution | OLED (2.36 MP) | OLED (3.69 MP) | OLED (3.69 MP) | OLED (5.76 MP) | OLED (5.76 MP) | OLED (3.69 MP) |
Viewfinder Magnification | x0,70 | x0,76 | x0,76 | x0,76 | x0,76 | x0,7 |
Wi-Fi / Bluetooth | YES | YES | YES | YES | YES | YES |
Articulated LCD screen | Fully articulated | Fully articulated | Fully articulated | Fully articulated | Fully articulated | Fully articulated |
LCD Resolution | 1,0 Mpts | 2,1 Mpts | 1,62 Mpts | 2,1 Mpts | 4.15 Mpts | 1,62 Mpts |
Touchscreen | Yes | Yes | Yes | Yes | Yes | Yes |
LCD diagonal | 7,5cm | 8cm | 7cm | 6,2cm | 8cm | 7cm |
Weather Sealed Body | Minimal | YES | YES | YES | YES | Yes |
Focus Points | 4779 | 5655 | 6072 | 5940 | 4779 | 4897 |
Low-Light AF Sensitivity | -5 / 18 EV | - 6 / 18 EV | -6,5 / 20 EV | -6 / 18 EV | -7.5 / 20 EV | -6,5 à 20 IL |
ISO (extended) | 100 - 40 000 (102 400) | 100 - 40 000 (102 400) | 100 - 51 200 (204 800) | 100 - 51 200 (102 400) | 100 - 102 400 (204 800) | 100 - 51 200 (204 800) |
Memory card | 1× SD, UHS-II (compatible) | 1× SD, UHS-II (compatible) | 2x SD UHS-II | 1xSD UHS-II, 1xCF Express | 1xSD UHS-II, 1xCF Express Type B | 2x SD UHS-II |
USB Version | USB-C 2.0 | USB-C 3.1 | USB-C 3.1 Gen 2 | USB-C 3.1 Gen 2 | USB-C 3.2 | USB-C 3.2 |
Continuous drive (Mechanical) | 8i/s (5i/s with Full AF) | 8i/s (5i/s with Full AF) | 12i/s | 12i/s | 12i/s | 12i/s (with Full AF) |
Continuous drive (Electronic) | 5i/s (4i/s with Full AF) | 8i/s (5i/s with Full AF) | 20i/s (with Full AF) | 20i/s (with Full AF) | 30i/s (with Full AF) | 40i/s (with Full AF) |
Video Maximum Resolution | 4K UHD 25p | 4K UHD 30p | 4K UHD 60p | 8K DCI 30p | 4K UHD 120p | 4K UHD 60p |
Shutter Speed Range (Mechanical) | 30 s - 1/4 000 s | 30 s - 1/8 000 s | 30 s - 1/8 000 s | 30 s - 1/8 000 s | 30 s - 1/8 000 s | 30 s - 1/8 000 s |
Video Max Frame rate (1080p) | 60 FPS | 60 FPS | 120 FPS | 80 FPS | 120 FPS | 180 FPS |
4K Video crop factor | 1,6x | 1,74x | 1,07x | 1x | 1x | 1x |
Canon C-Log Video | NO | NO | C-LOG HDR | C-LOG HDR (8K only) | C-LOG 3 | C-LOG 3 |
Recording limit | 30 min | 30 min | 30 min | 30 min | NO | 6h |
GPS | No | No | No | No | Yes | NO |
Time Lapse recording | Yes | No | No | No | Yes | YES |
So, which Canon canon full frame mirrorless camera is the best for you then?
I’ll start with a little aside about the EOS Ra, as it is so specific. With its 30.3MP 24×36 sensor capable of delivering beautiful high-sensitivity image quality, this makes it significantly more interesting than the APS-C sensor models Canon has offered so far. This model is a sweet luxury for people wanting to explore the universe even further.
What about the other four cameras?
Although its specifications are not extraordinary, the “small” EOS RP camera turns out to be particularly interesting to study. It is indeed the least expensive of all the full-frame cameras recently released. The main target is therefore photographers who have already used an expert compact, a mirrorless or a DSLR, but who want to switch to a full-frame mirrorless without breaking the bank. Thanks to the quality of the images generated by its full frame sensor, its overall reactivity and the efficiency of its Dual Pixel autofocus, the Canon EOS RP is a complete and pleasant camera to use on a day-to-day basis. Its compactness and light weight are considerable assets (200g less than its big brother, the EOS R).
With its first full frame mirrorless, the Canon EOS R is positioned in a mid-range model to seduce the amateur/passionate photographer.
With the EOS R, you get, in essence, the image and video quality of the 5D Mark IV but at a price close to that of the 6D Mark II. With a 30MP sensor, fantastic color reproduction, and built-in sensor autofocus, the EOS R can produce beautiful photos with precise focus. It also has remarkable low-light qualities. Unfortunately, while it is capable of delivering excellent image quality, there are mixed review about handling and ergonomics, and the EOS R’s video capabilities are considerably inferior to its rivals. Coupled with the excellent new RF lenses, this camera will be ideal for general and social photography, casual videographers and those looking for a full-frame mirrorless backup camera.
As far as the EOS R6 and R5 are concerned, we are moving into a higher range in my opinion!
The R5 offers a list of outstanding capabilities that will appeal to a variety of the most discerning professional and amateur photographers… and the most wealthy ones. Concretely, if you need to shoot 8K video internally – in both RAW and MP4 – and/or take very high-resolution pictures, the Canon EOS R5 and its 45MP sensor was made for you.
On the other hand, if these two aspects are not essential to you, you can without hesitation go for the Canon EOS R6, which offers a solid set of features too. The Canon EOS R6 appears to be a very well-balanced camera, the 20MP being sufficient for a wide range of photography, and it should be a perfect fit for both educated amateurs and professional photographers. The Canon R6 Mark II, does not bring in my opinion significant differences for considering it instead of the Mark I, even if longest shooting (LCD/viewfinder) and the possibilities of recording video in 6K60p without crop could be a plus for some people.
As for the Canon EOS R3, this is a very high-end mirrorless camera, right between the EOS R5 and the 1Dx Mark III, intended for professionals photographers who require a very high shutter speed and a more robust body! The EOS R3 is a real demonstration of Canon’s technologies: ultra-fast sensor, ultra-fast AF boosted with algorithms, 6K video… and, of course, the “famous” eye-controllable AF. Canon went all out to seduce the professional owners of an EOS 5D Mark IV or an EOS-1D X Mark III… This is simply the best camera from Canon now !
So, I hope this article on Canon full frame mirrorless cameras has helped you and you now see this new Canon’s world more clearly. Don’t hesitate to tell me what you thought of the article!
See you soon for more articles. Of course, I will update this one as soon as new Canon cameras are released.
As mentioned in the introduction, if you are still hesitating in your choice, don’t hesitate to go and check out the article on full frame Nikon mirrorless cameras. You might find what you are looking for.
See you soon,
Sylvain
PS : if you need EOS camera support, you’ll found on the following link all firmware update for these Canon mirrorless cameras.
Hi… This is the kind of article I was searching for! I’ve been a life long Nikon old-timer and want to change to Canon for my mirrorless transition. I found this article very helpful and informative as I am a totally unfamiliar with anything Canon. One of my main attractions to mirrorless is the new ‘eye focusing’ AF technology. Based on your article, I’m drawn to the IOS R6, however I’m not clear if the R6 incorporates the new ‘eye-focusing’ AF technology. Would you kindly clarify and provide detailed feedback. Thanks very much.
Hi Gary,
No, only the Canon R3 offers this option for now, not the R6.
Hi:
I’m wondering if you can clarify something:
In the comparison chart, you state that on one battery the R6 can shoot FEWER photos (380) if the operator is using the viewfinder rather than the LCD (electronic) view mode which can shoot 510 images with one battery. That makes no sense since the viewfinder does not require any power, so it should make the battery last way longer. It should shoot more images if the viewfinder is used and FEWER photos if the electronic or LCD panel is used.
Please explain if you could. Thanks so much,
Pete
Hi Pete,
It’s quite hard to explain the “why” and it seems that it will depends on brands. I’ve double check Sony and Canon cameras and it’s always the same. Here for Canon R6 (https://cam.start.canon/en/C004/manual/html/UG-09_Reference_0100.html). Confirmed by Canon.