Size and weight is a big decision factor when you are trying to find the ideal camera for your needs.
In this section, We are going to illustrate Panasonic ZS3 and Panasonic S1 side-by-side from the front, back and top in their relative dimensions. Panasonic ZS3 has external dimensions of 103 x 60 x 33 mm (4.06 x 2.36 x 1.3″) and weighs 229 g (0.50 lb / 8.08 oz) (including batteries). Panasonic S1 has external dimensions of 99 x 59 x 21 mm (3.9 x 2.32 x 0.83″) and weighs 117 g (0.26 lb / 4.13 oz) (including batteries).
Below you can see the front view size comparison of Panasonic ZS3 and Panasonic S1. Panasonic S1 is clearly the smaller of the two cameras. Its body is 4mm narrower, 1mm shorter and 12mm thinner than Panasonic ZS3.
Comparison image of Panasonic ZS3 and Panasonic S1 Size, Weight and External Dimensions - Front View
Here is the back view size comparison of Panasonic ZS3 and Panasonic S1.
Comparison image of Panasonic ZS3 and Panasonic S1 Size and Weight - Back View
Now lets look at the top view comparison of Panasonic ZS3 and Panasonic S1.
Top View Comparison image of Panasonic ZS3 and Panasonic S1 Size
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Panasonic S1 is significantly lighter (112g ) than the Panasonic ZS3 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither Panasonic Lumix DMC-ZS3 (Lumix DMC-TZ7) nor Panasonic Lumix DMC-S1 provides any type of weather sealing in their body, 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 ZS3's 3" LCD screen is slightly larger than Panasonic S1's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.