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 Panasonic G3 and Panasonic G100 side-by-side from the front, back and top in their relative dimensions. Panasonic G3 has external dimensions of 115 x 84 x 47 mm (4.53 x 3.31 x 1.85″) and weighs 336 g (0.74 lb / 11.85 oz) (including batteries). Panasonic G100 has external dimensions of 116 x 83 x 54 mm (4.57 x 3.27 x 2.13″) and weighs 352 g (0.78 lb / 12.42 oz) (including batteries).
Below you can see the front view size comparison of Panasonic G3 and Panasonic G100. Panasonic G3 is 1mm narrower and 7mm thinner than Panasonic G100 but it is also 1mm taller.
Here is the back view size comparison of Panasonic G3 and Panasonic G100.
Now lets look at the top view comparison of Panasonic G3 and Panasonic G100.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Panasonic G3 is 16g lighter than the Panasonic G100 but we don't think this will make a significant difference.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since both Panasonic G3 and Panasonic G100 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 Panasonic Lumix DMC-G3 nor Panasonic Lumix DC-G100 provides any type of weather sealing in their body, 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
Panasonic G3 and Panasonic G100's LCD screens has the same diagonal size of 3".
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 Selfie shots and video.