Does a trial judge have the authority to make a finding of incompetence without the benefit of an expert evaluation?

532.) "'[T]rial courts should be cautious about making an incompetence finding without benefit of an expert evaluation, though the judge's own observations of the defendant's in-court behavior will also provide key support for an incompetence finding and should be expressly placed on the record.' [Citation.]" (Id. at pp. 530-531.) A trial judge who "has observed the defendant on numerous occasions" "'will often prove best able to make more fine-tuned mental capacity decisions, tailored to the individualized circumstances of a particular defendant.' [Citation.]" (Id. at pp. 531-532, quoting Indiana v. Edwards, supra, 554 U.S. at p. 177.)