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 Nikon D4 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). Nikon D4 has external dimensions of 160 x 157 x 91 mm (6.3 x 6.18 x 3.58″) and weighs 1340 g (2.95 lb / 47.27 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-M5 III and the Nikon D4. Olympus E-M5 III is clearly the smaller of the two cameras. Its body is 35mm narrower, 72mm shorter and 41mm thinner than Nikon D4.
Here is the back view size comparison of the Olympus E-M5 III and Nikon D4.
Now lets look at the top view comparison of Olympus E-M5 III and Nikon D4.
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 (926g ) than the Nikon D4 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 Nikon D4 has a Full frame sensor and Olympus E-M5 III has a smaller Four Thirds sensor, Olympus E-M5 III's lenses for a similar focal length and aperture will generally be lighter and smaller than the Nikon D4 lenses.
Weather Sealing
Both the E-M5 Mark III and the D4 have weather sealings in their bodies, making them resistant to water and dust.
LCD Screen Size and Features
Nikon D4's 3.20" LCD screen is slightly larger than Olympus E-M5 III's 3 screen.
On the other hand, Olympus E-M5 III 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. On the other hand, Nikon D4 has a fixed type screen which provides almost no flexibility in shooting positions compared to E-M5 Mark III.