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 Nikon S3100 and Canon SX30 IS side-by-side from the front, back and top in their relative dimensions. Nikon S3100 has external dimensions of 94 x 58 x 18 mm (3.7 x 2.28 x 0.71″) and weighs 118 g (0.26 lb / 4.16 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 Nikon S3100 and Canon SX30 IS. Nikon S3100 is clearly the smaller of the two cameras. Its body is 29mm narrower, 34mm shorter and 90mm 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.
Nikon S3100 is significantly lighter (483g ) than the Canon SX30 IS which may become a big advantage especially on long walking trips.
Unfortunately neither Nikon Coolpix S3100 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
Nikon S3100 and Canon SX30 IS's LCD screens has the same diagonal size of 2.7".
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. Nikon S3100's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to SX30 IS.