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 Casio EX-S12 and Sony NEX-3 side-by-side from the front, back and top in their relative dimensions. Casio EX-S12 has external dimensions of 95 x 60 x 23 mm (3.74 x 2.36 x 0.91″) and weighs 111 g (0.24 lb / 3.92 oz) (including batteries). Sony NEX-3 has external dimensions of 117 x 62 x 33 mm (4.61 x 2.44 x 1.3″) and weighs 297 g (0.65 lb / 10.48 oz) (including batteries).
Below you can see the front-view size comparison of the Casio EX-S12 and the Sony NEX-3. Casio EX-S12 is clearly the smaller of the two cameras. Its body is 22mm narrower, 2mm shorter and 10mm thinner than Sony NEX-3. As you can tell, actually this is not a fair size comparison since Casio EX-S12 has a built-in lens but Sony NEX-3 doesn't. Once you put a lens on NEX-3, its thickness will increase significantly.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Casio EX-S12 is significantly lighter (186g ) than the Sony NEX-3 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 NEX-3, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Casio Exilim EX-S12 nor Sony Alpha NEX-3 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 Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Sony NEX-3's 3.00" LCD screen is slightly larger than Casio EX-S12's 2.7 screen.
In addition to the size advantage, Sony NEX-3 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, Casio EX-S12 has a fixed type screen which provides less flexibility in shooting positions compared to NEX-3.