Angle of view camera–subject distance to preserve the size of a subject, changing the angle of view can indirectly distort perspective, changing the apparent relative size of the subject and foreground. If the subject image size remains the same, then at any given aperture all lenses, wide angle and long lenses, will give the same depth of field. An example of how lens choice affects angle of view. This table shows the diagonal, horizontal, and vertical angles of view, in degrees, for lenses producing rectilinear images, when used with 36 mm × 24 mm format (that is, 135 film or full-frame 35mm digital
Trigonometric constants expressed in real radicals number of sides). This is because the sum of the angles of any "n"-gon is 180° × ("n" – 2) and so the measure of each angle of any regular "n"-gon is 180° × ("n" – 2) ÷ "n". Thus for example the entry "45°: square" means that, with "n" = 4, 180° ÷ "n" = 45°, and the number of degrees in each angle of a square is ("n" – 2) × 45° = 90°. For cube roots of non-real numbers that appear in this table, one has to take the principal value, that is the cube root with