I see lots of people on Etsy and ebay selling their traced celebrity faces and feel a bit turned off by that as you have to use an image that a photographer already put a great deal of effort and thought into. The image is really theirs. So I'm a bit miffed that I couldn't find the name of the photographer who took the original image here!
Obviously you use photographic reference for portraits of people in the news if you are a commercial illustrator or caricaturist... and I do think it's a good exercise every now and then. You still have to make lots of decisions and I think people who are not feeling too confident about drawing faces can gain a lot from it, teaches you to observe very closely :0)
Right, I think I may go back to bed or spend the rest of the day on the sofa because my head feels like a lead weight and my stomach keeps providing a rather ominous soundtrack to proceedings! :o(