Sony A57 weighs
618 g (1.36 lb / 21.80 oz) and has external dimensions of
132 x 98 x 81 mm (5.2 x 3.86 x 3.19″). Considering that the average weight of DSLR type cameras is 773g, Sony A57 is a remarkably light camera for its class. With a thickness of 81mm, it has an average thickness for its class.
Weight Comparison
DSLR Cameras
Thickness Comparison
DSLR Cameras
Here is the front and top view image of Sony A57 with the dimensions:
In order to give you a better idea about the real life size of Sony A57, we have added an image of how it looks next to a credit card and an AA type battery.
Now let's compare Sony A57 size with the camera that it replaced: Sony A55 (Check A57 vs A55). Sony A55 is 8mm narrower and 6mm shorter than Sony A57 but it is also 4mm thicker.
Below you can find the comparison of the weight and thickness of Sony A57 with its main competitors:
Sony A57 Size Compared to Main Competitors
Weather Sealing
Sony A57 doesn't have any environmental sealings on its body so you got to be extra careful to protect it against water and dust. If you shoot under these conditions very often, consider checking Top DSLR Cameras with Weather Sealing page.