If you stand close to someone, just inches away, their face will be distorted. The eye and brain working together can do a wonderful job of de-distorting the image but if you look carefully you can see that the sides of the face are narrower and the fall away is pronounced. As you move back a bit, still looking, you see the face widen a little and the nose become less prominent.
A camera is the same. If you plonk it close to the subject it will distort it.
The closer it is to the subject the more it will pull the nearest part of the subject forward and the more it will push the sides away. And conversely, the further you are away from the subject the more that different parts of the scene will compress from front to back.
You know how it is when you see cars in the distance coming towards you. They appear very close to one another. As they come closer, you see that the distance between them is greater than you thought.
Which is correct?
That’s more of a philosophical question, but for a photographer who want to work with this effect, he or she needs to know that standing further back compresses the scene from front to back. Even a face that is just a few inches from front to back will appear more flattened and wider when it is further away compared to when it is closes.
It is not the focal length of the lens. It is how far the camera is from the subject. If I use a short focal length lens and stand far back, the image will only fill a small part of the frame. If I am photographing a person, their face and body will not be distorted from what my eye would see.
If I move forward to fill the frame with a short focal length lens then the elements in the scene from front to back will separate more and give more space between them, and a face close up will be distorted, with nose protruding and face narrow as it seems to sweep away into the background/
The bottom line is that if I want to photograph a person and not distort the face, and I want to fill the frame, then I need a long focal length lens. That is why we have long focal length lenses.
