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 Ricoh G900 and Pentax K-5 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). Pentax K-5 has external dimensions of 131 x 97 x 73 mm (5.16 x 3.82 x 2.87″) and weighs 740 g (1.63 lb / 26.10 oz) (including batteries).
Below you can see the front-view size comparison of the Ricoh G900 and the Pentax K-5. Ricoh G900 is clearly the smaller of the two cameras. Its body is 13mm narrower, 31mm shorter and 40mm thinner than Pentax K-5. As you can tell, actually this is not a fair size comparison since Ricoh G900 has a built-in lens but Pentax K-5 doesn't. Once you put a lens on K-5, its thickness will increase significantly.
Here is the back view size comparison of the Ricoh G900 and Pentax K-5.
Now lets look at the top view comparison of Ricoh G900 and Pentax K-5.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Ricoh G900 is significantly lighter (493g ) than the Pentax K-5 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 K-5, the total kit will weigh much higher.
LCD Screen Size and Features
Ricoh G900 and Pentax K-5's LCD screens have the same diagonal size of 3.00 inches.
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.