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 ZS100 and Sony W810 side-by-side from the front, back and top in their relative dimensions. Panasonic ZS100 has external dimensions of 111 x 65 x 44 mm (4.37 x 2.56 x 1.73″) and weighs 312 g (0.69 lb / 11.01 oz) (including batteries). Sony W810 has external dimensions of 97 x 56 x 21 mm (3.82 x 2.2 x 0.83″) and weighs 111 g (0.24 lb / 3.92 oz) (including batteries).
Below you can see the front-view size comparison of the Panasonic ZS100 and the Sony W810. Sony W810 is clearly the smaller of the two cameras. Its body is 14mm narrower, 9mm shorter and 23mm thinner than Panasonic ZS100.
Here is the back view size comparison of the Panasonic ZS100 and Sony W810.
Now lets look at the top view comparison of Panasonic ZS100 and Sony W810.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Sony W810 is significantly lighter (201g ) than the Panasonic ZS100 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Panasonic Lumix DMC-ZS100 (Lumix DMC-TZ100) nor Sony Cyber-shot DSC-W810 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 ZS100's 3.00" LCD screen is slightly larger than Sony W810's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.