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 Pentax X90 and Olympus E-M10 III side-by-side from the front, back and top in their relative dimensions. Pentax X90 has external dimensions of 111 x 85 x 110 mm (4.37 x 3.35 x 4.33″) and weighs 428 g (0.94 lb / 15.10 oz) (including batteries). 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).
Below you can see the front-view size comparison of the Pentax X90 and the Olympus E-M10 III. Olympus E-M10 III is 1mm shorter and 60mm thinner than Pentax X90 but it is also 11mm wider. As you can tell, actually this is not a fair size comparison since Pentax X90 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 Pentax X90 and Olympus E-M10 III.
Now lets look at the top view comparison of Pentax X90 and Olympus E-M10 III.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Olympus E-M10 III is 18g lighter than the Pentax X90 but we don't think this will make a significant difference.
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 Pentax X90 nor Olympus OM-D E-M10 Mark III 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 Bridge Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-M10 III's 3.00" LCD screen is slightly larger than Pentax X90'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, Pentax X90 has a fixed type screen which provides less flexibility in shooting positions compared to E-M10 III.