Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Sony A7 III and Canon R3 side-by-side from the front, back and top in their relative dimensions. Sony A7 III has external dimensions of 127 x 96 x 74 mm (5 x 3.78 x 2.91″) and weighs 650 g (1.43 lb / 22.93 oz) (including batteries). Canon R3 has external dimensions of 150 x 143 x 87 mm (5.91 x 5.63 x 3.43″) and weighs 1015 g (2.24 lb / 35.80 oz) (including batteries).
Below you can see the front-view size comparison of the Sony A7 III and the Canon R3. Sony A7 III is clearly the smaller of the two cameras. Its body is 23mm narrower, 47mm shorter and 13mm thinner than Canon R3.
Here is the back view size comparison of the Sony A7 III and Canon R3.
Now lets look at the top view comparison of Sony A7 III and Canon R3.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Sony A7 III is significantly lighter (365g ) than the Canon R3 which may become a big advantage especially on long walking trips.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you also have to take into account the lenses that you will be using with these bodies. Since both Sony A7 III and Canon R3 have the same Full frame sized sensor, their lenses for a similar focal length and aperture will be similar in size and weight.
Weather Sealing
Both the A7 III and the R3 have weather sealings in their bodies, making them resistant to water and dust.
LCD Screen Size and Features
Canon R3's 3.20" LCD screen is slightly larger than Sony A7 III's 3″ screen.