Sony H300 has a 20.0MP 1/2.3" (6.17 x 4.55 mm ) sized CCD sensor and features Bionz(R) processor. On the other hand, Leica Q has a 24.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor.
Below you can see the H300 and Q Typ 116 sensor size comparison.
As seen above, Leica Q has a 30.8x Larger sensor area than Sony H300. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in same focal length and aperture.