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 Canon 400D and Casio EX-G1 side-by-side from the front, back and top in their relative dimensions. Canon 400D has external dimensions of 127 x 94 x 65 mm (5 x 3.7 x 2.56″) and weighs 556 g (1.23 lb / 19.61 oz) (including batteries). Casio EX-G1 has external dimensions of 104 x 64 x 20 mm (4.09 x 2.52 x 0.79″) and weighs 154 g (0.34 lb / 5.43 oz) (including batteries).
Below you can see the front view size comparison of Canon 400D and Casio EX-G1. Casio EX-G1 is clearly the smaller of the two cameras. Its body is 23mm narrower, 30mm shorter and 45mm thinner than Canon 400D. As you can tell, actually this is not a fair size comparison since Casio EX-G1 has a built-in lens but Canon 400D doesn't. Once you put a lens on 400D, its thickness will increase significantly.
Now lets look at the top view comparison of Canon 400D and Casio EX-G1.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Casio EX-G1 is significantly lighter (402g ) than the Canon 400D 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 400D, the total kit will weigh much higher.
LCD Screen Size and Features
Canon 400D and Casio EX-G1's LCD screens has the same diagonal size of 2.5".
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.