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 Fujifilm X-A1 and Nikon S640 side-by-side from the front, back and top in their relative dimensions. Fujifilm X-A1 has external dimensions of 117 x 67 x 39 mm (4.6 x 2.62 x 1.54″) and weighs 330 g (0.73 lb / 11.64 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 Fujifilm X-A1 and the Nikon S640. Nikon S640 is clearly the smaller of the two cameras. Its body is 26mm narrower, 12mm shorter and 18mm thinner than Fujifilm X-A1. As you can tell, actually this is not a fair size comparison since Nikon S640 has a built-in lens but Fujifilm X-A1 doesn't. Once you put a lens on X-A1, its thickness will increase significantly.
Here is the back view size comparison of the Fujifilm X-A1 and Nikon S640.
Now lets look at the top view comparison of Fujifilm X-A1 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 (200g ) than the Fujifilm X-A1 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 X-A1, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Fujifilm X-A1 nor Nikon Coolpix S640 provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Mirrorless Cameras with Weather Sealing Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Fujifilm X-A1's 3.00" LCD screen is slightly larger than Nikon S640's 2.7" screen.
In addition to the size advantage, Fujifilm X-A1 LCD screen also has a
Tilting feature where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels. On the other hand, Nikon S640 has a fixed type screen which provides less flexibility in shooting positions compared to X-A1.