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 Casio EX-Z450 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). Casio EX-Z450 has external dimensions of 81 x 56 x 21 mm (3.19 x 2.2 x 0.83″) and weighs 128 g (0.28 lb / 4.52 oz) (including batteries).
Below you can see the front view size comparison of Panasonic ZS3 and Casio EX-Z450. Casio EX-Z450 is clearly the smaller of the two cameras. Its body is 22mm narrower, 4mm shorter and 12mm thinner than Panasonic ZS3.
Here is the back view size comparison of Panasonic ZS3 and Casio EX-Z450.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Casio EX-Z450 is significantly lighter (101g ) than the Panasonic ZS3 which may become a big advantage especially on long walking trips.
Unfortunately neither Panasonic Lumix DMC-ZS3 (Lumix DMC-TZ7) nor Casio Exilim EX-Z450 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 and Casio EX-Z450's LCD screens has the same diagonal size of 3".
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.