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 Ricoh G900 and Sony A57 side-by-side from the front, back and top in their relative dimensions. Ricoh G900 has external dimensions of 118 x 66 x 33 mm (4.65 x 2.6 x 1.3″) and weighs 247 g (0.54 lb / 8.71 oz) (including batteries). Sony A57 has external dimensions of 132 x 98 x 81 mm (5.2 x 3.86 x 3.19″) and weighs 618 g (1.36 lb / 21.80 oz) (including batteries).
Below you can see the front view size comparison of Ricoh G900 and Sony A57. Ricoh G900 is clearly the smaller of the two cameras. Its body is 14mm narrower, 32mm shorter and 48mm thinner than Sony A57. As you can tell, actually this is not a fair size comparison since Ricoh G900 has a built-in lens but Sony A57 doesn't. Once you put a lens on A57, its thickness will increase significantly.
Now lets look at the top view comparison of Ricoh G900 and Sony A57.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Ricoh G900 is significantly lighter (371g ) than the Sony A57 which may become a big advantage especially on long walking trips.
Again, this comparison may not be very useful in real life as we are comparing the weight of a camera with a built-in lens to the body-only weight of an interchangeable lens camera. Once you put a lens on A57, the total kit will weigh much higher.
LCD Screen Size and Features
Ricoh G900 and Sony A57's LCD screens has the same diagonal size of 3".
On the other hand, Sony A57 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. Ricoh G900's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to A57.