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 Olympus FE-45 and Canon 1D MIII side-by-side from the front, back and top in their relative dimensions. Olympus FE-45 has external dimensions of 94 x 62 x 23 mm (3.7 x 2.44 x 0.91″) and weighs 142 g (0.31 lb / 5.01 oz) (including batteries). Canon 1D MIII has external dimensions of 156 x 157 x 80 mm (6.14 x 6.18 x 3.15″) and weighs 1335 g (2.94 lb / 47.09 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus FE-45 and the Canon 1D MIII. Olympus FE-45 is clearly the smaller of the two cameras. Its body is 62mm narrower, 95mm shorter and 57mm thinner than Canon 1D MIII. As you can tell, actually this is not a fair size comparison since Olympus FE-45 has a built-in lens but Canon 1D MIII doesn't. Once you put a lens on 1D MIII, its thickness will increase significantly.
Here is the back view size comparison of the Olympus FE-45 and Canon 1D MIII.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Olympus FE-45 is significantly lighter (1193g ) than the Canon 1D MIII 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 1D MIII, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the 1D MIII, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the FE-45.
LCD Screen Size and Features
Canon 1D MIII's 3.00" LCD screen is slightly larger than Olympus FE-45's 2.5" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.