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 Panasonic TS20 and Pentax Q-S1 side-by-side from the front, back and top in their relative dimensions. Panasonic TS20 has external dimensions of 101 x 58 x 19 mm (3.98 x 2.28 x 0.75″) and weighs 142 g (0.31 lb / 5.01 oz) (including batteries). Pentax Q-S1 has external dimensions of 105 x 58 x 34 mm (4.13 x 2.28 x 1.34″) and weighs 203 g (0.45 lb / 7.16 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic TS20 and the Pentax Q-S1. Panasonic TS20 is 4mm narrower and 15mm thinner than Panasonic TS20 but they have the same height of 58mm. As you can tell, actually this is not a fair size comparison since Panasonic TS20 has a built-in lens but Pentax Q-S1 doesn't. Once you put a lens on Q-S1, its thickness will increase significantly.
Here is the back view size comparison of the Panasonic TS20 and Pentax Q-S1.
Now lets look at the top view comparison of Panasonic TS20 and Pentax Q-S1.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic TS20 is significantly lighter (61g ) than the Pentax Q-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 Q-S1, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the TS20, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the Q-S1.
LCD Screen Size and Features
Pentax Q-S1's 3.00" LCD screen is slightly larger than Panasonic TS20's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.