Originally posted by emr This is an interesting topic. I'm a bit surprised by Wheatfield's advice. I'd guessed the opposite would work better. I'd assume that with some wide glass shot from close, the roundness of a round person would be exaggerated. But since I really do not know much about photography and lack the experience, better take his/her advice.
Remember, a 50 isn't really a wide lens. I'm presuming that a DSLR will be used, so the 50 is a short tele. The shorter lens will give somewhat less compression, which is a good thing with a bigger person, but it's not going to be obvious because the lens is still on the long side.
Try it yourself, take a half length picture from a person's eye level with something in the 70mm range and then take another from a foot higher with a 50mm lens (adjust the camera distance and angle to get a similar amount of the subject) and see the difference.