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 Panasonic FP8 and Olympus E-PM2 side-by-side from the front, back and top in their relative dimensions. Panasonic FP8 has external dimensions of 96 x 60 x 20 mm (3.78 x 2.36 x 0.79″) and weighs 151 g (0.33 lb / 5.33 oz) (including batteries). Olympus E-PM2 has external dimensions of 110 x 64 x 34 mm (4.33 x 2.52 x 1.34″) and weighs 269 g (0.59 lb / 9.49 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic FP8 and the Olympus E-PM2. Panasonic FP8 is clearly the smaller of the two cameras. Its body is 14mm narrower, 4mm shorter and 14mm thinner than Olympus E-PM2. As you can tell, actually this is not a fair size comparison since Panasonic FP8 has a built-in lens but Olympus E-PM2 doesn't. Once you put a lens on E-PM2, its thickness will increase significantly.
Now lets look at the top view comparison of Panasonic FP8 and Olympus E-PM2.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic FP8 is significantly lighter (118g ) than the Olympus E-PM2 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-PM2, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-FP8 nor Olympus PEN E-PM2 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
Olympus E-PM2's 3.00" LCD screen is slightly larger than Panasonic FP8's 2.7 screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.