Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Canon G1 X III and Panasonic GH5 side-by-side from the front, back and top in their relative dimensions. Canon G1 X III has external dimensions of 115 x 78 x 51 mm (4.53 x 3.07 x 2.01″) and weighs 399 g (0.88 lb / 14.07 oz) (including batteries). Panasonic GH5 has external dimensions of 139 x 98 x 87 mm (5.47 x 3.86 x 3.43″) and weighs 725 g (1.60 lb / 25.57 oz) (including batteries).
Below you can see the front view size comparison of Canon G1 X III and Panasonic GH5. Canon G1 X III is clearly the smaller of the two cameras. Its body is 24mm narrower, 20mm shorter and 36mm thinner than Panasonic GH5. As you can tell, actually this is not a fair size comparison since Canon G1 X III has a built-in lens but Panasonic GH5 doesn't. Once you put a lens on GH5, its thickness will increase significantly.
Here is the back view size comparison of Canon G1 X III and Panasonic GH5.
Now lets look at the top view comparison of Canon G1 X III and Panasonic GH5.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon G1 X III is significantly lighter (326g ) than the Panasonic GH5 which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on GH5, the total kit will weigh much higher.
Both G1 X III and GH5 have weather sealings in their body, making them resistant to water and dust.
LCD Screen Size and Features
Panasonic GH5's 3.2 LCD screen is slightly larger than Canon G1 X III's 3" screen.