I don’t like drawing from photographs although I am quite OK drawing from pictures of other people’s drawings and paintings. Or copying my own drawings.
My latest technique is to run a video of the person I am trying to draw in the background as well as using several photos of them to make a freehand pen sketch.
Of course there are various ways of tracing a photo of Boris Johnson, running a photo of him through various apps that produce something that looks like a drawing or painting or even using some type of camera lucidia. But to me doing this produces something artistically different to what I want to draw when I try to get the likeness of a person.
Drawing a likeness, particularly directly from a person, is a bit of a no win situation whether it comes out well or badly. Going a little way into the high country of the mind here, I think what I am trying to do is to produce a catalyst for the posteriori knowledge already in the mid of the person viewing the picture.