One fascinating aspect of this issue in this thread, of how best to create a natural perspective in archetecture, is the other issue of the true focal length of the average human eye.
If one does a Google search on this question, one gets a variety of answers ranging from 17mm to 50mm. What the heck's going on here?
So I picked up my D700 with 14-24 attached, and 50D with 17-55 attached, and stood in the corner of my lounge, about 1.5 metres from my laptop, chair and small table.
The chair was the closest to the camera, and the front door, diagonally at the opposite corner of the room about 8 metres away.
I stared at the door, then raised the camera to my eye, several times at various focal legths using both cameras.
My impressions are, at 14mm (full frame 35mm) the view through the finder appears to approximate to my eye's angle of view including the extreme peripheral vision which has totally lousy resolution and which is only good for movement detection. In fact the peripheral vision through two eyes might be slightly greater than a 14mm angle of view, full frame DSLR, but I have no doubt which photo would be sharper towards the edges, comparing the D700 at 14mm with a snapshot of my brain's impression.
What's also very obvious is that, at 14mm, my front door appears much smaller through the viewfinder than it does when not looking through the camera. The effect of 'smallness' of an object just 8 metres away continues at higher focal lengths until we reach about 45 to 50mm.
At 50mm, when I toggle between gazing through the viewfinder and staring straight at the door, I see no noticeable change in the size of the door. However, a 50mm angle of view crops off most of that peripheral vision.
I get the impression (just a rough impression) if I were able to take a recordable snapshot of my brain's impression of the view of the front door, then crop off all the peripheral fuzzy stuff (and some of that peripheral stuff is a lot fuzzier than the out-of-focus areas of a shot with a 50mm lens at F1, including the worst corner and edge degradation of any lens every made), then I would get a fairly decent analogy with a photo taken with a 50mm lens.
The attraction of wide-angle lenses is that the camera is able to record in fine detail scenes which the human eye cannot encompass from one, fixed perspective. The eye can of course move around and take in a very wide scene in all its detail, but not in one fixed stare, even if the eyeballs are moved.
That's why I find the following shot interesting, taken recently in Vienna. There's no perspective correction here, by the way. This is straight out of the camera, uncropped. D700 with 14mm at F16. (Sharp from big toe to infinity ).
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