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 Nikon D7000 and Nikon D5100 side-by-side from the front, back and top in their relative dimensions. Nikon D7000 has external dimensions of 132 x 105 x 77 mm (5.2 x 4.13 x 3.03″) and weighs 780 g (1.72 lb / 27.51 oz) (including batteries). Nikon D5100 has external dimensions of 128 x 97 x 79 mm (5.04 x 3.82 x 3.11″) and weighs 560 g (1.23 lb / 19.75 oz) (including batteries).
Below you can see the front view size comparison of Nikon D7000 and Nikon D5100. Nikon D5100 is 4mm narrower and 8mm shorter than Nikon D7000 but it is also 2mm thicker.
Now lets look at the top view comparison of Nikon D7000 and Nikon D5100.
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Nikon D5100 is significantly lighter (220g ) than the Nikon D7000 which may become a big advantage especially on long walking trips.
Also keep in mind that body weight is not the only deciding factor when comparing two interchangeable camera bodies, you have to also take into account the lenses that you will be using with these bodies. Since both Nikon D7000 and Nikon D5100 have the same Nikon F lens mount and APS-C sized sensors, lenses will not be a differentiator on total size of the system.
With its weather sealed body, we believe that D7000 has a big advantage over D5100 which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Nikon D7000 and Nikon D5100's LCD screens has the same diagonal size of 3".
On the other hand, Nikon D5100 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. Nikon D7000's LCD screen is a fixed type which provides almost no flexibility in shooting positions compared to D5100.