Angle of view
, angle of view
is the size of the image on the film
. Angle of view is affected by choice of lens; wide-angle lenses get considerably wider angle of view than telephoto lenses; with e.g. a fisheye lens recording up to 180° of a scene and the longest lenses recording less than 5°. Longer lenses tend to magnify the subject, compressing distance and (when focused on the foreground) blurring the background because of their shallower depth of field
. Wider lenses tend to magnify distance between objects while allowing greater depth of field. One result of using a wide angle lens in close proximity to the subject is an apparent perspective distortion
: parallel lines may appear to converge; with a fisheye lens, straight edges will appear to bend.
An example of how lens choice affects angle of view.
The photos above were taken by a 35 mm camera.
Focal lengths from top to bottom: 28 mm, 50 mm, 70 mm, 210 mm.
For a non-distorting, regular (non-fisheye) lens, the angle of view (α) can be calculated from the film dimension (d), and effective focal length (f) thus:
The effective focal length can be set equal to the focal length of the lens (F
), except in macro photography where the magnification (m
) must be taken into account: