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 RS1500 and Nikon 1 S1 side-by-side from the front, back and top in their relative dimensions. Pentax RS1500 has external dimensions of 114 x 58 x 28 mm (4.49 x 2.28 x 1.1″) and weighs 157 g (0.35 lb / 5.54 oz) (including batteries). Nikon 1 S1 has external dimensions of 102 x 61 x 30 mm (4.02 x 2.4 x 1.18″) and weighs 197 g (0.43 lb / 6.95 oz) (including batteries).
Below you can see the front-view size comparison of the Pentax RS1500 and the Nikon 1 S1. Pentax RS1500 is 3mm shorter and 2mm thinner than Nikon 1 S1 but it is also 12mm wider. As you can tell, actually this is not a fair size comparison since Pentax RS1500 has a built-in lens but Nikon 1 S1 doesn't. Once you put a lens on 1 S1, its thickness will increase significantly.
Here is the back view size comparison of the Pentax RS1500 and Nikon 1 S1.
Now lets look at the top view comparison of Pentax RS1500 and Nikon 1 S1.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Pentax RS1500 is significantly lighter (40g ) than the Nikon 1 S1 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 1 S1, the total kit will weigh much higher.
Weather Sealing
With its weather-sealed body, we believe that the RS1500 has a big advantage over the 1 S1 which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Nikon 1 S1's 3.00" LCD screen is slightly larger than Pentax RS1500's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.