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 A100 and Leica M-Monochrom side-by-side from the front, back and top in their relative dimensions. Nikon A100 has external dimensions of 95 x 59 x 20 mm (3.74 x 2.32 x 0.79″) and weighs 119 g (0.26 lb / 4.20 oz) (including batteries). Leica M-Monochrom has external dimensions of 139 x 80 x 37 mm (5.47 x 3.15 x 1.46″) and weighs 600 g (1.32 lb / 21.16 oz) (including batteries).
Below you can see the front-view size comparison of the Nikon A100 and the Leica M-Monochrom. Nikon A100 is clearly the smaller of the two cameras. Its body is 44mm narrower, 21mm shorter and 17mm thinner than Leica M-Monochrom. As you can tell, actually this is not a fair size comparison since Nikon A100 has a built-in lens but Leica M-Monochrom doesn't. Once you put a lens on M-Monochrom, its thickness will increase significantly.
Here is the back view size comparison of the Nikon A100 and Leica M-Monochrom.
Now lets look at the top view comparison of Nikon A100 and Leica M-Monochrom.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Nikon A100 is significantly lighter (481g ) than the Leica M-Monochrom 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 M-Monochrom, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Nikon Coolpix A100 nor Leica M-Monochrom 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 Compact Cameras with Weather Sealing Top Mirrorless Cameras with Weather Sealing
LCD Screen Size and Features
Nikon A100's 2.70" LCD screen is slightly larger than Leica M-Monochrom's 2.5 screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.