The Canon Vixia HF R40 has a maximum optical sensor size of 1/4.85". That's 20% more optical sensor size than the most common optical sensor size of 1/5.8". The optical sensor size of all video cameras of this age and spec ranges from 1/6" to 1/3".
Alternative video cameras that have a 1/4.85" optical sensor size currently available that you might want to look at include because of it's better review score, the Legria HF R48, or the Legria HF R406 both from Canon.
If the optical sensor size of this video camera is too small for you then you might want to look at the Vixia HF G20 (£22.83) (1/3 and higher rated), or the XA10 (£96.35) (1/3 and higher rated) both from Canon.