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-PL8 and Panasonic GX850 side-by-side from the front, back and top in their relative dimensions. Olympus E-PL8 has external dimensions of 115 x 67 x 38 mm (4.53 x 2.64 x 1.5″) and weighs 357 g (0.79 lb / 12.59 oz) (including batteries). Panasonic GX850 has external dimensions of 107 x 65 x 33 mm (4.21 x 2.56 x 1.3″) and weighs 269 g (0.59 lb / 9.49 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-PL8 and the Panasonic GX850. Panasonic GX850 is clearly the smaller of the two cameras. Its body is 8mm narrower, 2mm shorter and 5mm thinner than Olympus E-PL8.
Here is the back view size comparison of the Olympus E-PL8 and Panasonic GX850.
Now lets look at the top view comparison of Olympus E-PL8 and Panasonic GX850.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic GX850 is significantly lighter (88g ) than the Olympus E-PL8 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-PL8 and Panasonic GX850 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.
Unfortunately neither the Olympus PEN E-PL8 nor Panasonic Lumix DMC-GX850 (Lumix DMC-GX800 / Lumix DMC-GF9) provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-PL8 and Panasonic GX850's LCD screens have the same diagonal size of 3.00 inches.
Both cameras feature Tilting screens
where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels.