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 Canon 1D X and Nikon P510 side-by-side from the front, back and top in their relative dimensions. Canon 1D X has external dimensions of 158 x 164 x 83 mm (6.22 x 6.46 x 3.27″) and weighs 1340 g (including batteries). Nikon P510 has external dimensions of 120 x 83 x 102 mm (4.72 x 3.27 x 4.02″) and weighs 555 g (1.22 lb / 19.58 oz) (including batteries).
Below you can see the front-view size comparison of the Canon 1D X and the Nikon P510. Nikon P510 is 38mm narrower and 81mm shorter than Canon 1D X but it is also 19mm thicker. As you can tell, actually this is not a fair size comparison since Nikon P510 has a built-in lens but Canon 1D X doesn't. Once you put a lens on 1D X, its thickness will increase significantly.
Here is the back view size comparison of the Canon 1D X and Nikon P510.
Now lets look at the top view comparison of Canon 1D X and Nikon P510.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon P510 is significantly lighter (785g ) than the Canon 1D X 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 1D X, the total kit will weigh much higher.
Weather Sealing
With its weather-sealed body, we believe that the 1D X has a big advantage over the P510 which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Canon 1D X's 3.20" LCD screen is slightly larger than Nikon P510's 3 screen.