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Yes, Rusty - that's about right, and my specific problems with the ANON-ANGEL imagery have to do with exactly what you mention. Let me try and expound this as simply as possible (optical issues related to focal lenghts are notoriously difficult to explain in writing). As a matter of fact, the anomalous ANON-ANGEL imagery should help me illustrate what is definitely NOT possible in the real world of photography. Firstly though, let me list a couple of principles which we need to keep in mind - also as a way of clarifying a few things I have stated earlier:
RELATION BETWEEN FORE/BACKGROUND PROPORTIONS/PERSPECTIVES
1 - Zooming in or out with any lens
will NOT affect the relative sizes of foregrounds vs backgrounds.
2 - Fitting your camera with lenses of different focal lengths
will NOT, per se, alter the relative sizes of foregrounds vs backgrounds at any given, 'normal' distance from a subject (an exception being the barrel distortion produced when, for instance, a short lens is pointed extremely close to a person's face).
3 - What
WILL produce fore/background ratio variances, is when photographer
A (equipped with, say, a short 24mm lens) and photographer
B (equipped with, say, a longer 200mm lens) stand
at different distances from a given subject.
Let's say that Mr
A and Mr
B are both framing - from identical vantage points - a girl standing at the edge of a valley. In their viewfinders, they will see the exact same scenery (although Mr
A will see a much larger portion of the valley). Now, if Mr
B takes 30 steps backwards and
zooms in on the girl to make up for his displacement, 'his' valley will look proportionally larger to the girl than Mr
A's girl/valley ratio. The valley in Mr
B's viewfinder will look unnaturally close to the girl >>> 'focal distorsion'. (Also, if the girl isn't brightly lit by direct sunlight - or worse - in the shade of a tree, Mr
B will have to adjust /increase his lens aperture - and his picture will feature a totally blurred valley).
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With this said, let's take another look at the
ANON-
ANGEL imagery. I have precisely re-sized the two pairs of ANON / ANGEL frames in order to equalize the proportions of the objects seen in the two pairs of images.
I have called the first pair of frames "
the capped man frames". Let's have a look at them:
"ANON's capped man frame"
"ANGEL's capped man frame"
_______________
Well, everything seems to be quite ok and in order here - (apart from the extraordinary coincidence that both ANON and ANGEL captured such very similar frames). The foreground / background "
X" measure references I have drawn on this pair of images are all perfectly identical, which suggests ANON and ANGEL used identical lenses. SO FAR SO GOOD.
Now, let's take a look at this other pair of frames which I have called "
the cyclist frames". You will have to keep in mind that the ANON / ANGEL clips are very short and continuous, uninterrupted segments of 'footage' lasting less than 30 seconds:
ANON clip: http://www.youtube.com/watch?v=SbnrGC6mAHo#t=42s
ANGEL clip: http://www.youtube.com/watch?v=mMvqLtPyf78#t=11s
"ANON's cyclist frame"
"ANGEL's cyclist frame"
Well, the
"Z" measurement in
ANGEL's frame above is almost half (55%) as wide as my 'control measurement'
"X".
All of a sudden and inexplicably, the ANGEL foreground/backdrop ratio has shifted by as much as 45% !
So: if you wished to defend the authenticity of these images you would have to argue that:
"ANGEL changed his standard lens at some stage to a much shorter lens, he then ran down Southwards on Westside Highway so he could still capture that cyclist - and that grey car - as big as we seem them in ANON's frame. ANON didn't move, and that's why his X measurements remain constant - and that's why we see ANGEL's foreground-to-background-ratio shrinking by 45%."
Well, good luck with that!
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To put it VERY simply, I would conclude that these "WTC COLLAPSE CLIPS" were constructed like this: The lower part of these shots (showing street sceneries with cars, people and so forth) were filmed separately in some 'Hollywood' location - with several cameras placed at various angles, in order to simulate various vantage points - to be credited to various "amateur or professional cameramen". The upper part showing the dramatic "3D" WTC collapse animation (and a few surrounding buildings) was inserted in post-production. This complex 'layering' technique was prone to human error - and caused the many perspective aberrations we have been exposing throughout the years on this forum.