Take a headshot portrait (one where the head fills the page) using a 20mm lens.
Go on, do it. You know you can. And I mean a real 20mm lens, so if you have a 1.6 crop camera like a Digital Rebel you would use a 13mm lens; on a Nikon you would use a 14mm lens. Or that setting on your wide angle zoom lens.
You would get this – and thank you to the student who kindly volunteered to be pictured with, um, an enlarged nose:
Because that is what happens when you use a wide lens, because you have to be so close.
You see, it is not the lens that has the bad magic. It is your position right in front of his face.
Now use an 80mm lens (that would be a 50mm lens for crop factor camera users). That forces you to step back a couple of metres. Now you get this:
That’s a lot better, eh?
So the moral: portraits are best taken from a few metres away. Either that means you use a longer lens (80-135mm), or you avoid headshots where the subject is large so you have to get close.
And therefore yes, you can use a wide lens – just with a small subject, in the middle. So an environmental portrait with a wide angle lens is fine, if your subject is small and not near the picture’s edges. Otherwise, a long lens. On a crop camera, 50mm and longer!