Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Pentax K-S2 and Pentax K-S1 side-by-side from the front, back and top in their relative dimensions. Pentax K-S2 has external dimensions of 91 x 123 x 73 mm (3.58 x 4.84 x 2.87″) and weighs 678 g (1.49 lb / 23.92 oz) (including batteries). Pentax K-S1 has external dimensions of 121 x 93 x 70 mm (4.76 x 3.66 x 2.76″) and weighs 558 g (1.23 lb / 19.68 oz) (including batteries).
Below you can see the front view size comparison of Pentax K-S2 and Pentax K-S1. Pentax K-S1 is 2mm narrower and 3mm thinner than Pentax K-S2 but it is also 2mm taller.
Here is the back view size comparison of Pentax K-S2 and Pentax K-S1.
Now lets look at the top view comparison of Pentax K-S2 and Pentax K-S1.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Pentax K-S1 is significantly lighter (120g ) than the Pentax K-S2 which may become a big advantage especially on long walking trips.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since both Pentax K-S2 and Pentax K-S1 have the same Pentax KAF2 lens mount and APS-C sized sensors, lenses will not be a differentiator on total size of the system.
With its weather sealed body, we believe that K-S2 has a big advantage over K-S1 which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Pentax K-S2 and Pentax K-S1's LCD screens has the same diagonal size of 3".
On the other hand, Pentax K-S2 sports a Fully Articulated screen
which you can change the angle and position of the screen almost freely, making it possible to shoot from waist or over the head levels, and especially very useful for shooting selfies and video. Pentax K-S1's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to K-S2.