Size and weight are big decision factors when you are trying to find the ideal camera for your needs.
In this section, we are going to illustrate the Nikon L31 and Sony A700 side-by-side from the front, back and top in their relative dimensions. Nikon L31 has external dimensions of 96 x 59 x 29 mm (3.78 x 2.32 x 1.14″) and weighs 160 g (0.35 lb / 5.64 oz) (including batteries). Sony A700 has external dimensions of 142 x 105 x 80 mm (5.59 x 4.13 x 3.15″) and weighs 768 g (1.69 lb / 27.09 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon L31 and the Sony A700. Nikon L31 is clearly the smaller of the two cameras. Its body is 46mm narrower, 46mm shorter and 51mm thinner than Sony A700. As you can tell, actually this is not a fair size comparison since Nikon L31 has a built-in lens but Sony A700 doesn't. Once you put a lens on A700, its thickness will increase significantly.
Comparison image of the Nikon L31 and the Sony A700 Size, Weight and External Dimensions - Front View
Here is the back view size comparison of the Nikon L31 and Sony A700.
Comparison image of the Nikon L31 and the Sony A700 Size and Weight - Back View
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon L31 is significantly lighter (608g ) than the Sony A700 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 A700, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the A700, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the L31.
LCD Screen Size and Features
Sony A700's 3.00" LCD screen is slightly larger than Nikon L31's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.