technique - Why does the chair and the grandpa look bigger and inflated?

I Was watching one of the actually good movies. In one of the scenes the grandpa tries to "preach" the teens.

Here is the scene

Its not very obvious but for some reason the chair and the granpa looks like inflated while rest of the scene looks "smaller" . Why exactly?

Answer

This is a normal side-effect of using a 'wide' lens.

In photography, if the lens focal length is equal to the diagonal size of the camera sensor or film size then the result is an approximately 1x magnification image (such an image will seem neither wide nor narrow ... the angle of view will seem normal.)

If the focal length of the lens is shorter than this size, the magnification will be less than 1x and you will begin to see wide angle distortions.

A key effect of a 'wide' lens (in addition to having a wider angle of view) is that they also stretch the depth of a scene. If were shooting rooms in a home and wanted to make the rooms seem larger, you could use a moderately wide lens and this would result in the room seeming longer & deeper than it really is.

In this case, because grandpa's face is farther than the arm of the chair in the foreground, grandpa's face seems much farther away (and hence smaller) vs. the parts of him which are nearer (and hence seem larger).

Using a narrow/long lens reverses the effect. Instead of stretching the scene, those lenses compress the depth of the scene.