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 E-300 and Panasonic FS42 side-by-side from the front, back and top in their relative dimensions. Olympus E-300 has external dimensions of 147 x 85 x 64 mm (5.79 x 3.35 x 2.52″) and weighs 624 g (1.38 lb / 22.01 oz) (including batteries). Panasonic FS42 has external dimensions of 98 x 55 x 22 mm (3.86 x 2.17 x 0.87″) and weighs 132 g (0.29 lb / 4.66 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-300 and the Panasonic FS42. Panasonic FS42 is clearly the smaller of the two cameras. Its body is 49mm narrower, 30mm shorter and 42mm thinner than Olympus E-300. As you can tell, actually this is not a fair size comparison since Panasonic FS42 has a built-in lens but Olympus E-300 doesn't. Once you put a lens on E-300, 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.
Panasonic FS42 is significantly lighter (492g ) than the Olympus E-300 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-300, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Olympus E-300 / EVOLT E-300 nor Panasonic Lumix DMC-FS42 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 DSLR Cameras with Weather Sealing Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Panasonic FS42's 2.50" LCD screen is slightly larger than Olympus E-300's 1.8" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.