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 Olympus E-M5 III and Panasonic GH3 side-by-side from the front, back and top in their relative dimensions. Olympus E-M5 III has external dimensions of 125 x 85 x 50 mm (4.92 x 3.35 x 1.97″) and weighs 414 g (0.91 lb / 14.60 oz) (including batteries). Panasonic GH3 has external dimensions of 133 x 93 x 82 mm (5.24 x 3.66 x 3.23″) and weighs 550 g (1.21 lb / 19.40 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-M5 III and the Panasonic GH3. Olympus E-M5 III is clearly the smaller of the two cameras. Its body is 8mm narrower, 8mm shorter and 32mm thinner than Panasonic GH3.
Here is the back view size comparison of the Olympus E-M5 III and Panasonic GH3.
Now lets look at the top view comparison of Olympus E-M5 III and Panasonic GH3.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Olympus E-M5 III is significantly lighter (136g ) than the Panasonic GH3 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 Olympus E-M5 III and Panasonic GH3 have the same Micro Four Thirds lens mount and Four Thirds sized sensors, lenses will not be a differentiator on total size of the system.
Weather Sealing
Both the E-M5 Mark III and the GH3 have weather sealings in their bodies, making them resistant to water and dust.
LCD Screen Size and Features
Olympus E-M5 III and Panasonic GH3's LCD screens have the same diagonal size of 3.00 inches.
Both cameras feature
Fully Articulating screens where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels. Fully articulating screens are also useful for taking Selfies and video.