Sony a7R IIIA vs Canon EOS M

This is a full comparison between the cameras Sony a7R IIIA and Canon EOS M. We compare them by looking at the categories you see below.

Manufacturing

Sony a7R IIIA is manufacturered by Sony but Canon EOS M is from Canon. Both Sony and Canon are well known brands though.

Sony a7R IIIA were released 2021 and Canon EOS M was released 2012. That is a 9 years difference. In tech, this period can be of interest since technology is always improving, etc.

Camera Released
Sony a7R IIIA 2021
Canon EOS M 2012

Type of camera

Both these cameras are Mirrorless cameras. No difference there.

Sensors / crop factor

These cameras have different sensors. Sony a7R IIIA has a "Sony Full Frame"-sensor while Canon EOS M has a "Canon APS-C"-sensor, and their difference in sensors will also affect the crop factor and experience focal length. See the table below.

Camera Focal length, 50mm f/1.8 **
Sony a7R IIIA 50 mm
Full-frame sensor
No crop factor/focal length multiplier
Canon EOS M 80 mm
Canon APS-C sensor
Crop factor/focal length multiplier by * 1.6

** Experienced focal length when using a lens such as a common "50mm f/1.8"

Learn more about crop factor and focal length multiplier here:
Camera selection can affect the focal length (Sony)
Camera selection can affect the focal length (Canon)

Resolution

Sony a7R IIIA has a 42 MP (Megapixels) resolution while Canon EOS M has 18 MP. If we break down this in more detail this is the data behind the numbers:

Camera Megapixels
Sony a7R IIIA 42 MP
42177408 pixels
7952 x 5304
Canon EOS M 18 MP
17915904 pixels
5184 x 3456

Sony a7R IIIA has a 135 % larger resolution than Canon EOS M. This could give you more details in the picture but also a possibility to crop more in the pictures, afterward while editing the pictures, if needed that is.

ISO range

Sony a7R IIIA has a larger ISO-range than Canon EOS M. Sony a7R IIIA has an ISO range that stretches from 100 to 32000 while Canon EOS M has 100 to 12800.

Camera ISO Range
Sony a7R IIIA 100-32000
Canon EOS M 100-12800

Autofocus and lens compatibility

Both of these cameras have a built-in autofocus motor. Some lenses, that support autofocus, do not have an autofocus motor of their own but this won't cause any problems with these two cameras.

Worth mentioning is that Canon EOS M belongs to the Canon EOS M-system and needs an adapter to work with Canons EF, EF-S, MP-E, and TS-E lenses. You can read more about this adapter here:
Canon Lens Mount Adapter EF-EOS M

Here is a complete overview of which lenses work with each camera:
Lens compatibility chart for Sony a7R IIIA
Lens compatibility chart for Canon EOS M

Pictures per second

Depending on what you are shooting the FPS, or frames/pictures per second, can definitely be of interest. Sony a7R IIIA can shoot up to 10 pictures per seconds and Canon EOS M can shoot up to 4,3 pictures per seconds.

Camera FPS (Frames per second)
Sony a7R IIIA 10
Canon EOS M 4,3

Ability to record movies

It is becoming more and more popular to record movies with digital cameras.

In this case, both Sony a7R IIIA and Canon EOS M can shoot movies.

Weight

The weight of the camera can be an extremely important factor, especially if the camera is about to be used, or carried around, for several hours at a time.

Sony a7R IIIA weighs 657 gr (equal to 1.45 lb) which is 120% heavier than Canon EOS M and its 298 gr (or 0.66 lb).

Camera Weight
Sony a7R IIIA 657 gr
1.45 lb
Canon EOS M 298 gr
0.66 lb

Sony a7R IIIA vs Canon EOS M Specs

Below you will find the complete and detailed technical specs for both Sony a7R IIIA and Canon EOS M, next to each other. Each category of data is a link to an article covering the subject, giving you a deeper understanding so you can better understand the strengths and weaknesses of the two camera models.

Product
Sony a7R IIIA
Canon EOS M
Name Sony a7R IIIA Canon EOS M
Manufacturer Sony Canon
Release Date and Price
Sony a7R IIIA
Canon EOS M
Release Year 2021 2012
Release Date 2021-04-07 2012-07-23
MSRP 3199 USD 799 USD
Buy it today
Camera Type
Sony a7R IIIA
Canon EOS M
Camera Type Mirrorless Mirrorless
Sensor
Sony a7R IIIA
Canon EOS M
Sensor Size Full Frame (approx 36 x 24 mm) APS-C (approx 22.3 x 14.9 mm)
Sensor Type BSI-CMOS CMOS
Resolution 7952 x 5304 pixels 5184 x 3456 pixels
Megapixels 42 MP 18 MP
Image Processor BIONZ X DIGIC 5
Image
Sony a7R IIIA
Canon EOS M
ISO Range 100 - 32000 100 - 12800
White Balance Presets 10 6
Custom White Balance Yes Yes
Image Stabilization Yes
(Sensor-Shift (5-axis))
No
Image Stabilization CIPA Rating 5.5 stops 0 stops
Uncompressed format RAW RAW
Optics & Focus
Sony a7R IIIA
Canon EOS M
Autofocus Motor Yes Yes
Autofocus Contract Detect (sensor)
Phase Detect
Multi Area
Center
Selective Single Point
Tracking
Single
Continuous
Touch
Face Detection
LiveView
Contract Detect (sensor)
Phase Detect
Multi Area
Selective Single Point
Single
Continuous
Face Detection
LiveView
Focus Points 399 31
Lens Mount Sony E

See Compatible Lenses
Canon EF-M

See Compatible Lenses
Focal Length Multiplier Full frame
No multiplier
Example:
24 mm remains 24 mm
50 mm remains 50 mm
100 mm remains 100 mm
200 mm remains 200 mm
APS-C Sensor
1.6x multiplier
Example:
24 mm becomes 38 mm
50 mm becomes 80 mm
100 mm becomes 160 mm
200 mm becomes 320 mm
Screen & Viewfinder
Sony a7R IIIA
Canon EOS M
Articulated LCD Tilting Fixed
Screen size 3” 3”
Screen dots 2360000 1040000
Touch screen Yes Yes
Screen type TFT LCD Clear View II TFT LCD
Live view Yes Yes
Viewfinder Type Electronic No Viewfinder
Viewfinder Coverage 100%
Viewfinder Magnification 0.78x
Viewfinder Resolution 3686400 0
Photography features
Sony a7R IIIA
Canon EOS M
Frames per second 10 fps 4,3 fps
Minimum Shutter Speed 30 seconds 60 seconds
Maximum Shutter Speed 1/8000 seconds 1/4000 seconds
Built-in Flash No No
Built-in Flash Range N/A N/A
External Flash Yes Yes
Self-Timer Yes Yes
Time-lapse No No
Metering modes Multi
Center Weighted
Spot
Multi
Center Weighted
Spot
Partial
Exposure Compensation +/- 5 (at 1/3 EV, 1/2 EV steps) +/- 3 (at 1/3 EV, 1/2 EV steps)
Videography features
Sony a7R IIIA
Canon EOS M
Video recording Yes Yes
Video format MPEG4
XAVC-S
AVCHD
MPEG4
H.264
Video resolution 1920 x 1080
3840 x 2160
1280 x 720
1920 x 1080
Built-in Microphone Yes Yes
Built-in Speakers Yes Yes
Storage
Sony a7R IIIA
Canon EOS M
Memory Card SD/SDHC
SD/SDHC
Connectivity
Sony a7R IIIA
Canon EOS M
HDMI Output Yes Yes
Microphone Port Yes No
Headphone Port Yes No
Wireless Yes
Built-in (802.11b/g/n + NFC + Bluetooth)
Yes
Eye-Fi Connected
Remote Control Yes (wired, wireless, smartphone) No
GPS No Yes
Optional via GP-E2
Body & Dimensions
Sony a7R IIIA
Canon EOS M
Enviromentally sealed Yes No
Battery Battery Pack Battery Pack
Battery Details NP-FZ100 lithium-ion battery and charger
Lithium-Ion LP-E12 rechargeable battery & charger
Battery Life (CIPA) 650 shots 230 shots
Width 127 mm 109 mm
Height 96 mm 66 mm
Depth 74 mm 32 mm
Weight 657 gram 298 gram