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 Canon S120 and Panasonic ZR3 side-by-side from the front, back and top in their relative dimensions. Canon S120 has external dimensions of 100 x 59 x 29 mm (3.94 x 2.32 x 1.14″) and weighs 217 g (0.48 lb / 7.65 oz) (including batteries). Panasonic ZR3 has external dimensions of 98 x 55 x 26 mm (3.86 x 2.17 x 1.02″) and weighs 159 g (0.35 lb / 5.61 oz) (including batteries).
Below you can see the front-view size comparison of the Canon S120 and the Panasonic ZR3. Panasonic ZR3 is clearly the smaller of the two cameras. Its body is 2mm narrower, 4mm shorter and 3mm thinner than Canon S120.
Here is the back view size comparison of the Canon S120 and Panasonic ZR3.
Now lets look at the top view comparison of Canon S120 and Panasonic ZR3.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic ZR3 is significantly lighter (58g ) than the Canon S120 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Canon PowerShot S120 nor Panasonic Lumix DMC-ZR3 (Lumix DMC-ZX3) 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
Canon S120's 3.00" LCD screen is slightly larger than Panasonic ZR3's 2.7 screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.