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 Sony A77 II and Nikon D780 side-by-side from the front, back and top in their relative dimensions. Sony A77 II has external dimensions of 143 x 104 x 81 mm (5.63 x 4.09 x 3.19″) and weighs 647 g (1.43 lb / 22.82 oz) (including batteries). Nikon D780 has external dimensions of 144 x 116 x 76 mm (5.67 x 4.57 x 2.99″) and weighs 840 g (1.85 lb / 29.63 oz) (including batteries).
Below you can see the front view size comparison of Sony A77 II and Nikon D780. Sony A77 II is 1mm narrower and 12mm shorter than Nikon D780 but it is also 5mm thicker.
Here is the back view size comparison of Sony A77 II and Nikon D780.
Now lets look at the top view comparison of Sony A77 II and Nikon D780.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Sony A77 II is significantly lighter (193g ) than the Nikon D780 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 have to also take into account the lenses that you will be using with these bodies. Since Nikon D780 has a Full frame sensor and Sony A77 II has a smaller APS-C sensor, Sony A77 II's lenses for a similar focal length and aperture will generally be lighter and smaller than the Nikon D780 lenses.
Both A77 II and D780 have weather sealings in their body, making them resistant to water and dust.
LCD Screen Size and Features
Nikon D780's 3.2" LCD screen is slightly larger than Sony A77 II's 3" screen.