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 S1 and Panasonic ZS50 side-by-side from the front, back and top in their relative dimensions. Pentax S1 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). Panasonic ZS50 has external dimensions of 111 x 65 x 34 mm (4.37 x 2.56 x 1.34″) and weighs 243 g (0.54 lb / 8.57 oz) (including batteries).
Below you can see the front-view size comparison of the Pentax S1 and the Panasonic ZS50. Pentax S1 is 7mm shorter and 6mm thinner than Panasonic ZS50 but it is also 3mm wider.
Here is the back view size comparison of the Pentax S1 and Panasonic ZS50.
Now lets look at the top view comparison of Pentax S1 and Panasonic ZS50.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Pentax S1 is significantly lighter (86g ) than the Panasonic ZS50 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Pentax Optio S1 nor Panasonic Lumix DMC-ZS50 (Lumix DMC-TZ70) 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 Compact Cameras with Weather Sealing
LCD Screen Size and Features
Panasonic ZS50's 3.00" LCD screen is slightly larger than Pentax S1's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.