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p.17 #2 · Where does the 3D look come from? | |
This is an outstanding example of what is trying to be demonstrated here with regard to 3D. I think the most compelling issue is that none of us have been able to articulate what causes the 3D effect. But when you see it, you know it is there
Amen to that. That's what has made this thread so fascinating. The effect is something so visceral, and yet it continues to resist analysis. It reminds me of a quote: "Water is two parts hydrogen and one part oxygen. But there is also a third thing that makes it water, and nobody knows what that is."
I used my recently acquired 200/f1.8 in battle for the first time yesterday. It has great 3D, unbelievable sharpness at f1.8, and interstingly to me it does that trick of making light cling to edges like no other lens I have ever seen (camera jpeg, iso 800, f1.8):


Here are those weird edges again:

I am sure the strange edge effects are caused by the very large entrance pupil of the lens. One side of the lens is seeing darkness, while the other, due to parallax, isn't. Hence the strange impression that the light is bending around the edge of the object. Surely that is something that can help with 3D. In extreme cases is cuts the subject out from the background, but presumably in less extreme cases it only does so subliminally. When you think about it, every edge, in every picture, must be doing this to some extent, all the time. In this case the sharp black edge is clearly more sharply focussed than the cloth it outlines, which suggests that it may be the result of interference rather than resolved detail.
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