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 P500 and Panasonic GM1 side-by-side from the front, back and top in their relative dimensions. Nikon P500 has external dimensions of 116 x 84 x 10 mm (4.57 x 3.31 x 4.06″) and weighs 494 g (1.09 lb / 17.43 oz) (including batteries). Panasonic GM1 has external dimensions of 99 x 55 x 30 mm (3.88 x 2.16 x 1.2″) and weighs 204 g (0.45 lb / 7.20 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon P500 and the Panasonic GM1. Panasonic GM1 is clearly the smaller of the two cameras. Its body is 17mm narrower, 29mm shorter and 73mm thinner than Nikon P500. As you can tell, actually this is not a fair size comparison since Nikon P500 has a built-in lens but Panasonic GM1 doesn't. Once you put a lens on GM1, its thickness will increase significantly.
Here is the back view size comparison of the Nikon P500 and Panasonic GM1.
Now lets look at the top view comparison of Nikon P500 and Panasonic GM1.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Panasonic GM1 is significantly lighter (290g ) than the Nikon P500 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 GM1, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Nikon Coolpix P500 nor Panasonic Lumix DMC-GM1 provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Bridge Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Nikon P500 and Panasonic GM1's LCD screens have the same diagonal size of 3.00 inches.
On the other hand, Nikon P500 features a
Tilting screen where you can change the angle of the screen to make it easier to shoot from waist or over-the-head levels whereas the Panasonic GM1 has a fixed type screen which provides less flexibility in shooting positions compared to P500.