I'm not saying that you should photograph everything with a short lens and then crop later to get your composition. But I am saying that you should determine your camera to subject distance to set your perspective and the relationship between items in the photograph and then select the lens focal length that fills the frame appropriately. Don't blame your lens(es) for perspective distortion (expansion or compression of the scene).
Here is a set of 3 images. I'm using a mannequin here instead of human so that there would be no movement between the photographs. One was taken with a 200mm lens, one with a 35mm lens, and one with a 16mm lens. The fourth image takes the 200mm and the 16mm images and combines them in separate layers in Photoshop. I then set the blending mode to "difference" to show how the two images compare. The pixel and noise structure of the two images accounts for the variations inside the facial area. But if you look at the outline of the face, you will see that it is exactly the same in both images. Changing the focal length did not change the perspective. Can you tell which image was taken with which focal length lens?
|200mm and 16mm images overlayed|
on each other in Photoshop's "Difference"
blending mode. The facial shape and
features are the same.
|200mm lens from 8' away|
|35mm lens from 8' away|
|16mm lens from 8' away. Notice that|
the relationship between objects
in the scene are the same even with
the widely varied focal lengths used
And to round out the comparison, here are three photos taken with the 200, 35, and 16mm lenses where the camera to subject distance was changed to try to maintain the approximate same size of the face in the frame.
|200mm lens from 8' away. Facial features|
are flattened. Nose, eyes, and ears are
all similar in size. The face appears slightly
wider than "normal"
|35mm lens from about 2' away. Facial|
features are more pronounced. The nose
is larger than the ears. The face is
narrower than "normal"
|16mm lens from a few inches away.|
Facial features are even more distorted.
The nose comes forward, the ears are
much smaller. The face is much narrower
Remember, a shorter lens doesn't cause the perspective change. But it does allow you to move in closer so that you get that distortion. And a long lens doesn't compress depth. Blow up the center section and you will find they match (like in the first three images above). Photographs taken with different focal length lenses, but from the same camera position, show exactly the same perspective in the section of the scene that is common to all the different angles of view of the various lenses.
Thanks for putting up with this again!