Lens Focal Length: Normal, Short, Long, Special Lenses

  Lens focal length is the most important characteristic of a lens. One of the prime advantages of a single·lens reflex camera or a view camera is the interchangeability of its lenses; the reason photographers own more than one lens is so that they can change lens focal length. … PDF: Lens Focal Length, The Basic Difference Between Lenses   Normal Focal Length The Most Like Human Vision A lens of normal focal length, as you might expect from the name,  produces an image on film that seems normal when compared with human vision. The image includes about the same angle of view as the human eye Read more