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 Sony TX66 and Panasonic ZS40 side-by-side from the front, back and top in their relative dimensions. Sony TX66 has external dimensions of 93 x 54 x 13 mm (3.66 x 2.13 x 0.51″) and weighs 109 g (0.24 lb / 3.84 oz) (including batteries). Panasonic ZS40 has external dimensions of 111 x 64 x 34 mm (4.37 x 2.52 x 1.34″) and weighs 240 g (0.53 lb / 8.47 oz) (including batteries).
Below you can see the front-view size comparison of the Sony TX66 and the Panasonic ZS40. Sony TX66 is clearly the smaller of the two cameras. Its body is 18mm narrower, 10mm shorter and 21mm thinner than Panasonic ZS40.
Here is the back view size comparison of the Sony TX66 and Panasonic ZS40.
Now lets look at the top view comparison of Sony TX66 and Panasonic ZS40.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Sony TX66 is significantly lighter (131g ) than the Panasonic ZS40 which may become a big advantage especially on long walking trips.
Weather Sealing
Unfortunately neither the Sony Cyber-shot DSC-TX66 nor Panasonic Lumix DMC-ZS40 (Lumix DMC-TZ60) 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
Sony TX66's 3.30" LCD screen is slightly larger than Panasonic ZS40's 3" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.