Angle of view of the eye

[Eric Meyer <74415.1305@CompuServe.COM>]

To:  >INTERNET:Leica-users@mejac.palo-alto.ca.us

     This whole notion of the "normal lens" as something that
exactly mimics the human eye is absurd.  One does need a term
for the range of focal lengths that are not clearly either wide-angle
or long-focus -- though for that, a noncommittal word like
"midrange" would be more suitable.  The mathematics of emulsion size
and focal length provide a useful way to compare lenses across
formats, but haggling over a precise definition of "normal" focal
length (43mm or whatever) in a given format is silly without a truly
meaningful standard for what is "normal".

     As Henning has pointed out twice now, the eye has both central
and peripheral vision; which is "normal"?  Further, one must ask how
the eye will in turn view a finished photograph, as opposed to the
scene where it was made, and at what size and distance -- seldom, I
think, as a life-sized mural, so what can be truly "normal" about
any particular angle of view in a modest-sized photograph?

     That leaves only the issue of perspective, and even here,
normal is as normal does, not an exclusive function of focal length,
but also of use.  The results from any lens from 35-90mm will look
fairly "normal" much of the time.  Even a 20mm (held level) or 200mm
lens can take perfectly natural-looking photographs, if objects
within the field aren't at too great a range of distances.  Of
course, most any lens can also be used to produce effects that call
attention to itself, if desired.

     No focal length whatever is intrinsically and uniquely "normal".

                                  --  Eric Meyer.