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 Pentax Q7 and Canon G15 side-by-side from the front, back and top in their relative dimensions. Pentax Q7 has external dimensions of 102 x 58 x 34 mm (4.02 x 2.28 x 1.34″) and weighs 200 g (0.44 lb / 7.05 oz) (including batteries). Canon G15 has external dimensions of 107 x 76 x 40 mm (4.21 x 2.99 x 1.57″) and weighs 352 g (0.78 lb / 12.42 oz) (including batteries).
Below you can see the front-view size comparison of the Pentax Q7 and the Canon G15. Pentax Q7 is clearly the smaller of the two cameras. Its body is 5mm narrower, 18mm shorter and 6mm thinner than Canon G15. As you can tell, actually this is not a fair size comparison since Canon G15 has a built-in lens but Pentax Q7 doesn't. Once you put a lens on Q7, its thickness will increase significantly.
Here is the back view size comparison of the Pentax Q7 and Canon G15.
Now lets look at the top view comparison of Pentax Q7 and Canon G15.
Weight is another important factor, especially when deciding on a camera that you want to carry with you all day.
Pentax Q7 is significantly lighter (152g ) than the Canon G15 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 Q7, the total kit will weigh much higher.
Weather Sealing
Unfortunately neither the Pentax Q7 nor Canon PowerShot G15 provides any type of weather sealing in their bodies, so you have to give extra care especially when you are shooting outdoors. If weather sealing is a must-have feature for you, check these sections: Top Mirrorless Cameras with Weather Sealing Top Compact Cameras with Weather Sealing
LCD Screen Size and Features
Pentax Q7 and Canon G15'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.