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 Nikon P90 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). Nikon P90 has external dimensions of 83 x 114 x 99 mm (3.27 x 4.49 x 3.9″) and weighs 400 g (0.88 lb / 14.11 oz) (including batteries).
Below you can see the front-view size comparison of the Olympus E-M10 III and the Nikon P90. Olympus E-M10 III is 30mm shorter and 49mm thinner than Nikon P90 but it is also 39mm wider. As you can tell, actually this is not a fair size comparison since Nikon P90 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 Nikon P90.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon P90 is 10g lighter than the Olympus E-M10 III 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 Olympus OM-D E-M10 Mark III nor Nikon Coolpix P90 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 Bridge Cameras with Weather Sealing
LCD Screen Size and Features
Olympus E-M10 III and Nikon P90's LCD screens have the same diagonal size of 3.00 inches.
Both cameras feature
Tilting screens where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels.