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 Casio EX-Z450 and Olympus E-M1 side-by-side from the front, back and top in their relative dimensions. Casio EX-Z450 has external dimensions of 81 x 56 x 21 mm (3.19 x 2.2 x 0.83″) and weighs 128 g (0.28 lb / 4.52 oz) (including batteries). Olympus E-M1 has external dimensions of 130 x 94 x 63 mm (5.13 x 3.68 x 2.48″) and weighs 497 g (1.10 lb / 17.53 oz) (including batteries).
Below you can see the front view size comparison of Casio EX-Z450 and Olympus E-M1. Casio EX-Z450 is clearly the smaller of the two cameras. Its body is 49mm narrower, 38mm shorter and 42mm thinner than Olympus E-M1. As you can tell, actually this is not a fair size comparison since Casio EX-Z450 has a built-in lens but Olympus E-M1 doesn't. Once you put a lens on E-M1, its thickness will increase significantly.
Here is the back view size comparison of Casio EX-Z450 and Olympus E-M1.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Casio EX-Z450 is significantly lighter (369g ) than the Olympus E-M1 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 E-M1, the total kit will weigh much higher.
Thanks to the weather sealed body of E-M1, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to EX-Z450.
LCD Screen Size and Features
Casio EX-Z450 and Olympus E-M1's LCD screens has the same diagonal size of 3".
On the other hand, Olympus E-M1 features a Tilting screen
where you can change the angle of the screen to make it easier to shoot from waist or over the head levels whereas the Casio EX-Z450 has a fixed type screen which provides less flexibility in shooting positions compared to E-M1.