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 Nikon S6100 and Pentax K-30 side-by-side from the front, back and top in their relative dimensions. Nikon S6100 has external dimensions of 98 x 58 x 27 mm (3.86 x 2.28 x 1.06″) and weighs 175 g (0.39 lb / 6.17 oz) (including batteries). Pentax K-30 has external dimensions of 130 x 97 x 71 mm (5.12 x 3.82 x 2.8″) and weighs 650 g (1.43 lb / 22.93 oz) (including batteries).
Below you can see the front view size comparison of Nikon S6100 and Pentax K-30. Nikon S6100 is clearly the smaller of the two cameras. Its body is 32mm narrower, 39mm shorter and 44mm thinner than Pentax K-30. As you can tell, actually this is not a fair size comparison since Nikon S6100 has a built-in lens but Pentax K-30 doesn't. Once you put a lens on K-30, its thickness will increase significantly.
Comparison image of Nikon S6100 and Pentax K-30 Size, Weight and External Dimensions - Front View
Now lets look at the top view comparison of Nikon S6100 and Pentax K-30.
Top View Comparison image of Nikon S6100 and Pentax K-30 Size
Weight is another important factor especially when deciding on a camera that you want to carry with you all day.
Nikon S6100 is significantly lighter (475g ) than the Pentax K-30 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-30, the total kit will weigh much higher.
Weather Sealing
Thanks to the weather sealed body of K-30, you can use this camera with more confidence under conditions where there is risk of exposure to water and dust compared to S6100.
LCD Screen Size and Features
Nikon S6100 and Pentax K-30's LCD screens has the same diagonal size of 3".
Unfortunately, both cameras has fixed screens so they don't tilt or flip in directions.