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 IV and Pentax VS20 side-by-side from the front, back and top in their relative dimensions. Olympus E-M10 IV has external dimensions of 122 x 84 x 49 mm (4.8 x 3.31 x 1.93″) and weighs 383 g (0.84 lb / 13.51 oz) (including batteries). Pentax VS20 has external dimensions of 111 x 61 x 38 mm (4.37 x 2.4 x 1.5″) and weighs 235 g (0.52 lb / 8.29 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-M10 IV and the Pentax VS20. Pentax VS20 is clearly the smaller of the two cameras. Its body is 11mm narrower, 23mm shorter and 11mm thinner than Olympus E-M10 IV. As you can tell, actually this is not a fair size comparison since Pentax VS20 has a built-in lens but Olympus E-M10 IV doesn't. Once you put a lens on E-M10 IV, its thickness will increase significantly.
Here is the back view size comparison of the Olympus E-M10 IV and Pentax VS20.
Now lets look at the top view comparison of Olympus E-M10 IV and Pentax VS20.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Pentax VS20 is significantly lighter (148g ) than the Olympus E-M10 IV 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 IV, the total kit will weigh much higher.
Unfortunately neither the Olympus OM-D E-M10 IV nor Pentax Optio VS20 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 IV and Pentax VS20's LCD screens have the same diagonal size of 3.00 inches.
On the other hand, Olympus E-M10 IV features a Tilting screen
where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels whereas the Pentax VS20 has a fixed type screen which provides less flexibility in shooting positions compared to E-M10 IV.