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 D80 and Olympus TG-820 iHS side-by-side from the front, back and top in their relative dimensions. Nikon D80 has external dimensions of 132 x 103 x 77 mm (5.2 x 4.06 x 3.03″) and weighs 668 g (1.47 lb / 23.56 oz) (including batteries). Olympus TG-820 iHS has external dimensions of 101 x 65 x 26 mm (3.98 x 2.56 x 1.02″) and weighs 206 g (0.45 lb / 7.27 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon D80 and the Olympus TG-820 iHS. Olympus TG-820 iHS is clearly the smaller of the two cameras. Its body is 31mm narrower, 38mm shorter and 51mm thinner than Nikon D80. As you can tell, actually this is not a fair size comparison since Olympus TG-820 iHS has a built-in lens but Nikon D80 doesn't. Once you put a lens on D80, its thickness will increase significantly.
Now lets look at the top view comparison of Nikon D80 and Olympus TG-820 iHS.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Olympus TG-820 iHS is significantly lighter (462g ) than the Nikon D80 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 D80, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the TG-820 iHS, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the D80.
LCD Screen Size and Features
Olympus TG-820 iHS's 3.00" LCD screen is slightly larger than Nikon D80's 2.5" screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.