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-M10 III and Panasonic XS1 side-by-side from the front, back and top in their relative dimensions. Olympus E-M10 III has external dimensions of 122 x 84 x 50 mm (4.8 x 3.31 x 1.97″) and weighs 410 g (0.90 lb / 14.46 oz) (including batteries). Panasonic XS1 has external dimensions of 94 x 54 x 14 mm (3.7 x 2.13 x 0.55″) and weighs 103 g (0.23 lb / 3.63 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-M10 III and the Panasonic XS1. Panasonic XS1 is clearly the smaller of the two cameras. Its body is 28mm narrower, 30mm shorter and 36mm thinner than Olympus E-M10 III. As you can tell, actually this is not a fair size comparison since Panasonic XS1 has a built-in lens but Olympus E-M10 III doesn't. Once you put a lens on E-M10 III, its thickness will increase significantly.
Here is the back view size comparison of the Olympus E-M10 III and Panasonic XS1.
Now lets look at the top view comparison of Olympus E-M10 III and Panasonic XS1.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic XS1 is significantly lighter (307g ) than the Olympus E-M10 III 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-M10 III, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Olympus OM-D E-M10 Mark III nor Panasonic Lumix DMC-XS1 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 Mirrorless Cameras with Weather Sealing Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-M10 III's 3.00" LCD screen is slightly larger than Panasonic XS1's 2.7" screen.
In addition to the size advantage, Olympus E-M10 III LCD screen also has a
Tilting feature where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels. On the other hand, Panasonic XS1 has a fixed type screen which provides less flexibility in shooting positions compared to E-M10 III.