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-PM1 and Panasonic TS3 side-by-side from the front, back and top in their relative dimensions. Olympus E-PM1 has external dimensions of 110 x 64 x 34 mm (4.33 x 2.52 x 1.34″) and weighs 265 g (0.58 lb / 9.35 oz) (including batteries). Panasonic TS3 has external dimensions of 103 x 64 x 27 mm (4.06 x 2.52 x 1.06″) and weighs 197 g (0.43 lb / 6.95 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-PM1 and the Panasonic TS3. Olympus E-PM1 has the same height with Panasonic TS3. On the other hand, with a width of 110mm, it is 7 wider and also with a thickness of 34mm, it is 7mm thicker than Panasonic TS3. As you can tell, actually this is not a fair size comparison since Panasonic TS3 has a built-in lens but Olympus E-PM1 doesn't. Once you put a lens on E-PM1, its thickness will increase significantly.
Here is the back view size comparison of the Olympus E-PM1 and Panasonic TS3.
Now lets look at the top view comparison of Olympus E-PM1 and Panasonic TS3.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic TS3 is significantly lighter (68g ) than the Olympus E-PM1 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-PM1, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the TS3, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the E-PM1.
LCD Screen Size and Features
Olympus E-PM1's 3.00" LCD screen is slightly larger than Panasonic TS3's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.