That norm gives me a tool to use to control/manipulate how viewers, myself included, view the scene in print on the wall. It allows me to choose if they, or I, see normal or flattened or whatever perspective.
The flat medium also isn't the issue here.
When viewing a scene through your camera using most any lens designed to provide proper rectilinear perspective, the scene looks normal through the viewfinder. The scene does not look weird compared say the grid lines we see in the camera. (I'm assuming well corrected lenses here and I'm leaving out lens distortions, like barrel and pincushion, purposefully.)
The normal looking view seen in most cameras, is a projection on a flat surface, the focusing screen or ground glass.
The quote was excerpted from here http://en.wikipedia.org/wiki/Perspec...ject_distance)Photograph viewing distance
Photographs are ordinarily viewed at a distance approximately equal to their diagonal. When viewed at this distance, the distortion effects created by the angle of view of the capture are apparent. However, theoretically, if one views pictures exhibiting extension (wide angle) distortion at a closer distance, thus widening the angle of view of the presentation, then the phenomenon abates. Similarly, viewing pictures exhibiting compression (telephoto) distortion from a greater distance, thus narrowing the angle of view of the presentation, reduces the effect. In both cases, at some critical distance, the apparent distortion disappears completely.
Okay so here's an example from a local guy http://www.billproudphotography.com/pages/H212.htm Bill shot that on 4x5 Velvia, as I remember he said he used a 90mm lens.
The small sizes we can see on the Internet don't do ths "portrait" justice, the person centered in the arch is just so small that they gets missed. In person though, where the short edge of the print is in the 30-40" range that person draws you closer to the print, as does the natural angle of the shot. Viewed in person and closer than one might normally view a print that size it is incredible and starts filling the viewer's peripheral vision.