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 Ricoh G900 and Panasonic GM1 side-by-side from the front, back and top in their relative dimensions. Ricoh G900 has external dimensions of 118 x 66 x 33 mm (4.65 x 2.6 x 1.3″) and weighs 247 g (0.54 lb / 8.71 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 Ricoh G900 and Panasonic GM1. Panasonic GM1 is clearly the smaller of the two cameras. Its body is 19mm narrower, 11mm shorter and 3mm thinner than Ricoh G900. As you can tell, actually this is not a fair size comparison since Ricoh G900 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 Ricoh G900 and Panasonic GM1.
Now lets look at the top view comparison of Ricoh G900 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 (43g ) than the Ricoh G900 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.
LCD Screen Size and Features
Ricoh G900 and Panasonic GM1's LCD screens has the same diagonal size of 3.00".
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.