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 Z5 and OM System OM-5 side-by-side from the front, back and top in their relative dimensions. Nikon Z5 has external dimensions of 134 x 101 x 70 mm (5.28 x 3.98 x 2.76″) and weighs 675 g (1.49 lb / 23.81 oz) (including batteries). OM System OM-5 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).
Below you can see the front-view size comparison of the Nikon Z5 and the OM System OM-5. OM System OM-5 is clearly the smaller of the two cameras. Its body is 9mm narrower, 16mm shorter and 20mm thinner than Nikon Z5.
Here is the back view size comparison of the Nikon Z5 and OM System OM-5.
Now lets look at the top view comparison of Nikon Z5 and OM System OM-5.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
OM System OM-5 is significantly lighter (261g ) than the Nikon Z5 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 Z5 has a Full frame sensor and OM System OM-5 has a smaller Four Thirds sensor, OM System OM-5's lenses for a similar focal length and aperture will generally be lighter and smaller than the Nikon Z5 lenses.
Weather Sealing
Both the Z5 and the OM-5 have weather sealings in their bodies, making them resistant to water and dust.
LCD Screen Size and Features
Nikon Z5's 3.20" LCD screen is slightly larger than OM System OM-5's 3 screen.