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 Canon G12 and Panasonic S3 side-by-side from the front, back and top in their relative dimensions. Canon G12 has external dimensions of 112 x 76 x 48 mm (4.41 x 2.99 x 1.89″) and weighs 401 g (0.88 lb / 14.14 oz) (including batteries). Panasonic S3 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 Canon G12 and Panasonic S3. Panasonic S3 is clearly the smaller of the two cameras. Its body is 13mm narrower, 17mm shorter and 27mm thinner than Canon G12.
Here is the back view size comparison of Canon G12 and Panasonic S3.
Now lets look at the top view comparison of Canon G12 and Panasonic S3.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Panasonic S3 is significantly lighter (284g ) than the Canon G12 which may become a big advantage especially on long walking trips.
Unfortunately neither Canon PowerShot G12 nor Panasonic Lumix DMC-S3 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
Canon G12's 2.8" LCD screen is slightly larger than Panasonic S3's 2.7" screen.
Moreover, Canon G12 sports a Fully Articulated screen
which you can change the angle and position of the screen almost freely, making it possible to shoot from waist or over the head levels, and especially very useful for shooting selfies and video. On the other hand, Panasonic S3 has a fixed type screen which provides almost no flexibility in shooting positions compared to G12.