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 S640 and Canon G15 side-by-side from the front, back and top in their relative dimensions. 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). Canon G15 has external dimensions of 107 x 76 x 40 mm (4.21 x 2.99 x 1.57″) and weighs 352 g (0.78 lb / 12.42 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon S640 and the Canon G15. Nikon S640 is clearly the smaller of the two cameras. Its body is 16mm narrower, 21mm shorter and 19mm thinner than Canon G15.
Here is the back view size comparison of the Nikon S640 and Canon G15.
Now lets look at the top view comparison of Nikon S640 and Canon G15.
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 (222g ) than the Canon G15 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Nikon Coolpix S640 nor Canon PowerShot G15 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 Compact Cameras with Weather Sealing
LCD Screen Size and Features
Canon G15's 3.00" 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.