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 D4s and Nikon S640 side-by-side from the front, back and top in their relative dimensions. Nikon D4s has external dimensions of 160 x 157 x 91 mm (6.3 x 6.18 x 3.58″) and weighs 1350 g (2.98 lb / 47.62 oz) (including batteries). Nikon S640 has external dimensions of 91 x 55 x 21 mm (3.58 x 2.17 x 0.83″) and weighs 130 g (0.29 lb / 4.59 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon D4s and the Nikon S640. Nikon S640 is clearly the smaller of the two cameras. Its body is 69mm narrower, 102mm shorter and 70mm thinner than Nikon D4s. As you can tell, actually this is not a fair size comparison since Nikon S640 has a built-in lens but Nikon D4s doesn't. Once you put a lens on D4s, its thickness will increase significantly.
Here is the back view size comparison of the Nikon D4s and Nikon S640.
Now lets look at the top view comparison of Nikon D4s and Nikon S640.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon S640 is significantly lighter (1220g ) than the Nikon D4s 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 D4s, the total kit will weigh much higher.
Weather Sealing
With its weather-sealed body, we believe that the D4s has a big advantage over the S640 which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Nikon D4s's 3.20" LCD screen is slightly larger than Nikon S640's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.