I have a question for the technical types in this site. God knows there are enough of you, engineer, scientific types here. Some of us right brained or no brain types need your help.

Here goes;

Please explain the phenomina we know as distortion in, for instance;
When we take a full length portrait of a person with a 50mm on a 35mm camera, it is fine. If we move close and do a tight headshot, we distort the features, ie, the nose comes forward and the cheeks push back.

Does this same thing happen in larger format cameras. In my experience it seems to happen in 6x6 so we use a 150mm lens for headshots.

However in 4x5 very few photographer use a 300mm lens, most just use something like a 210-240mm. If we move in real close with these lenses do they also cause the same kind of distortion.

Thanks in advance

Michael McBlane