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 SX120 IS and Canon SX30 IS side-by-side from the front, back and top in their relative dimensions. Canon SX120 IS has external dimensions of 111 x 71 x 45 mm (4.37 x 2.8 x 1.77″) and weighs 285 g (0.63 lb / 10.05 oz) (including batteries). Canon SX30 IS has external dimensions of 123 x 92 x 108 mm (4.84 x 3.62 x 4.25″) and weighs 601 g (1.32 lb / 21.20 oz) (including batteries).
Below you can see the front view size comparison of Canon SX120 IS and Canon SX30 IS. Canon SX120 IS is clearly the smaller of the two cameras. Its body is 12mm narrower, 21mm shorter and 63mm thinner than Canon SX30 IS.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Canon SX120 IS is significantly lighter (316g ) than the Canon SX30 IS which may become a big advantage especially on long walking trips.
Unfortunately neither Canon PowerShot SX120 IS nor Canon PowerShot SX30 IS 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 Top Bridge Cameras with Weather Sealing
LCD Screen Size and Features
Canon SX120 IS's 3" LCD screen is slightly larger than Canon SX30 IS's 2.7" screen.
On the other hand, Canon SX30 IS 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, Canon SX120 IS has a fixed type screen which provides almost no flexibility in shooting positions compared to SX30 IS.