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 Sony W810 and Nikon D7100 side-by-side from the front, back and top in their relative dimensions. Sony W810 has external dimensions of 97 x 56 x 21 mm (3.82 x 2.2 x 0.83″) and weighs 111 g (0.24 lb / 3.92 oz) (including batteries). Nikon D7100 has external dimensions of 136 x 107 x 76 mm (5.35 x 4.21 x 2.99″) and weighs 765 g (1.69 lb / 26.98 oz) (including batteries).
Below you can see the front-view size comparison of the Sony W810 and the Nikon D7100. Sony W810 is clearly the smaller of the two cameras. Its body is 39mm narrower, 51mm shorter and 55mm thinner than Nikon D7100. As you can tell, actually this is not a fair size comparison since Sony W810 has a built-in lens but Nikon D7100 doesn't. Once you put a lens on D7100, its thickness will increase significantly.
Here is the back view size comparison of the Sony W810 and Nikon D7100.
Now lets look at the top view comparison of Sony W810 and Nikon D7100.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Sony W810 is significantly lighter (654g ) than the Nikon D7100 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 D7100, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the D7100, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the W810.
LCD Screen Size and Features
Nikon D7100's 3.20" LCD screen is slightly larger than Sony W810's 2.7" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.