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 WG-4 and Pentax K-01 side-by-side from the front, back and top in their relative dimensions. Ricoh WG-4 has external dimensions of 124 x 64 x 33 mm (4.88 x 2.52 x 1.3″) and weighs 230 g (0.51 lb / 8.11 oz) (including batteries). Pentax K-01 has external dimensions of 122 x 79 x 58 mm (4.8 x 3.11 x 2.28″) and weighs 561 g (1.24 lb / 19.79 oz) (including batteries).
Below you can see the front-view size comparison of the Ricoh WG-4 and the Pentax K-01. Ricoh WG-4 is 15mm shorter and 25mm thinner than Pentax K-01 but it is also 2mm wider. As you can tell, actually this is not a fair size comparison since Ricoh WG-4 has a built-in lens but Pentax K-01 doesn't. Once you put a lens on K-01, its thickness will increase significantly.
Now lets look at the top view comparison of Ricoh WG-4 and Pentax K-01.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Ricoh WG-4 is significantly lighter (331g ) than the Pentax K-01 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-01, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather-sealed body of the WG-4, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to the K-01.
LCD Screen Size and Features
Ricoh WG-4 and Pentax K-01'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.