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 Sigma fp and Ricoh GR III side-by-side from the front, back and top in their relative dimensions. Sigma fp has external dimensions of 113 x 70 x 45 mm (4.45 x 2.76 x 1.77″) and weighs 422 g (0.93 lb / 14.89 oz) (including batteries). Ricoh GR III has external dimensions of 109 x 62 x 33 mm (4.29 x 2.44 x 1.3″) and weighs 257 g (0.57 lb / 9.07 oz) (including batteries).
Below you can see the front-view size comparison of the Sigma fp and the Ricoh GR III. Ricoh GR III is clearly the smaller of the two cameras. Its body is 4mm narrower, 8mm shorter and 12mm thinner than Sigma fp. As you can tell, actually this is not a fair size comparison since Ricoh GR III has a built-in lens but Sigma fp doesn't. Once you put a lens on fp, its thickness will increase significantly.
Here is the back view size comparison of the Sigma fp and Ricoh GR III.
Now lets look at the top view comparison of Sigma fp and Ricoh GR III.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Ricoh GR III is significantly lighter (165g ) than the Sigma fp 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 fp, the total kit will weigh much higher.
Weather Sealing
With its weather-sealed body, we believe that the fp has a big advantage over the GR III which doesn't provide any kind of environmental sealing.
LCD Screen Size and Features
Sigma fp's 3.20" LCD screen is slightly larger than Ricoh GR III's 3 screen.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.