Can a witness testify as to their opinions and legal conclusions?

Ruano contends that the trial court erred by allowing witnesses to invade the province of the jury by testifying as to their opinions and legal conclusions. A witness not testifying as an expert may offer opinion testimony so long as it is "(a) [r]ationally based on the perception of the witness; and (b) [h]elpful to a clear understanding of his testimony." (Evid. Code, 800.) Opinions as to whether a defendant is guilty or innocent of the charges "are inadmissible because they are of no assistance to the trier of fact." (People v. Torres (1995) 33 Cal.App.4th 37, 47.)