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 Nikon S6400 and Panasonic GH4 side-by-side from the front, back and top in their relative dimensions. Nikon S6400 has external dimensions of 95 x 58 x 27 mm (3.74 x 2.28 x 1.06″) and weighs 150 g (0.33 lb / 5.29 oz) (including batteries). Panasonic GH4 has external dimensions of 133 x 93 x 84 mm (5.24 x 3.66 x 3.31″) and weighs 560 g (1.23 lb / 19.75 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon S6400 and the Panasonic GH4. Nikon S6400 is clearly the smaller of the two cameras. Its body is 38mm narrower, 35mm shorter and 57mm thinner than Panasonic GH4. As you can tell, actually this is not a fair size comparison since Nikon S6400 has a built-in lens but Panasonic GH4 doesn't. Once you put a lens on GH4, its thickness will increase significantly.
Here is the back view size comparison of the Nikon S6400 and Panasonic GH4.
Now lets look at the top view comparison of Nikon S6400 and Panasonic GH4.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon S6400 is significantly lighter (410g ) than the Panasonic GH4 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 GH4, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the GH4, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the S6400.
LCD Screen Size and Features
Nikon S6400 and Panasonic GH4's LCD screens have the same diagonal size of 3.00 inches.
On the other hand, Panasonic GH4 sports a
Fully Articulated screen which you can change the angle and position of the screen almost freely, making it possible to shoot from waist or over-the-head levels, and especially very useful for shooting selfies and video. Nikon S6400's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to GH4.