Cone of vision, optimal angle of view
The cone of vision is the angle of vision - including both eyes - delivering an undistorted image.
It is maximally about 60 degree. The optimal angle of view is about 15 degree, corresponding to an angle of view of looking at a postcard from a distance of about 50 cm, at a chair from about 4 meter or at a car from about 8 m. Images within this angle are projected on the central part of the retina (fovea), the part of the retina of the eye providing maximal optical resolution. Thus objects outside this angle, but still within the cone of vision, cannot be optimally perceived without moving the eyes or turning the head.
Image 1 shows a scenery pictured involving an angle of view of about 45 degree, image 2 presents the same scenery as a composition consisting of three pictures exhibiting each an angle of view of 15 degree.
The form of the objects in-between image 1 and image 2 show no notable difference. Image 1 shows more expression of spatial depth than image 2, image 2 appears as more friendly than image 1.
To create e.g. a drawing of this scenery reflecting its friendliness is best done by using the center part of the image to establish the basic frame-work. To win on friendliness but to diminish the expression of spatial depth, is done by slightly decreasing the inclination of the centrally converging lines (*). Note that a mathematically rather irrelevant change of this parameter, has a considerable emotional impact.
( * No such measure would be needed in regard of image 3, as the expression of depth is in this scenery very welcome. )