The Vixia HF R42 has a maximum optical sensor size of 1/4.85". That's 20% more optical sensor size than a 1/5.8" video camera, which is the most frequently found optical sensor size. Small sensor size video cameras that have been available for a similar time to the Vixia HF R42 optical sensor sizes range from 1/6" (worst) to 1/3" (best).
It may also be worth considering one of the other video cameras that have a 1/4.85" optical sensor size currently available including because of it's better review score, the Vixia HF R40 ($399.00), or the Legria HF R406 both from Canon.
If you want a camcorder with a bigger optical sensor size then you might also want to consider the Canon Vixia HF G20 ($799.99) (1/3 and higher rated), or the Sony HVR-Z7 ($5,775.99) (1/3 and higher rated).