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 Q and Nikon P310 side-by-side from the front, back and top in their relative dimensions. Pentax Q has external dimensions of 98 x 57 x 31 mm (3.86 x 2.24 x 1.22″) and weighs 180 g (0.40 lb / 6.35 oz) (including batteries). Nikon P310 has external dimensions of 103 x 58 x 32 mm (4.06 x 2.28 x 1.26″) and weighs 194 g (0.43 lb / 6.84 oz) (including batteries).
Below you can see the front-view size comparison of the Pentax Q and the Nikon P310. Pentax Q is clearly the smaller of the two cameras. Its body is 5mm narrower, 1mm shorter and 1mm thinner than Nikon P310. As you can tell, actually this is not a fair size comparison since Nikon P310 has a built-in lens but Pentax Q doesn't. Once you put a lens on Q, its thickness will increase significantly.
Here is the back view size comparison of the Pentax Q and Nikon P310.
Now lets look at the top view comparison of Pentax Q and Nikon P310.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Pentax Q is 14g lighter than the Nikon P310 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 Q, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Pentax Q nor Nikon Coolpix P310 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
Pentax Q and Nikon P310's LCD screens have the same diagonal size of 3.00 inches.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.