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General Photography Technique Discussion on General Photography Technique |
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#21
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Try it and see...you're defying the laws of physics if you think you can move the size relationships around without moving your position
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Adey http://www.birdforum.net/pp_gallery/...00/ppuser/1805 'Write when there is something you know: and not before: and not too damned much after' Ernest Hemingway |
#22
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Don, re your post number 12.
I think you are talking about the compression of planes that you get with long lenses. This is known as ariel perspective. But perspectve as I was using the term relates to the size of objects relative to each other. Christine's pictures illustrate this admirably. Or have I misunderstood you. What I was trying to give was a mathematical knock down proof that the relative size of objects in a picture depends only on subject distance and not at all on focal length. That is why I looked at the ratio ha/hb. John |
#23
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John,
My interpretation of the effect of changes in presective was as in Christine post. May well be wrong. Brain getting a bit fried. One thing I will say, you have livened up our evening. I will go through this again tomorrow with a clearer head and daylight. Don |
#24
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The point is that if christine had walked up the drive with the 100mm lens and stood in the correct spot you would not be able to tell the difference between the 100mm and 170mm shots. The same applies to DOF.
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Rob ----------------------------------------------------- Solar powered Box Brownie Mk2 Captain Sunshine, to be such a man as he, and walk so pure between the earth and the sea. WPF Gallery Birdforum Gallery |
#25
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DOF Don, now there's another story; but I haven't the nerve to start another thread.
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#26
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#27
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Don |
#28
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John |
#29
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Don
The effect in Christine shots is changing perspective. But stickly speaking it is due to changing the magnification factor which is a by-product of changing the focal lenght. I know this may sound pedantic but it becomes important when trying to understand the science. If this effect was purely a function of focal lenght then moving closer would never give the same view.
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Rob ----------------------------------------------------- Solar powered Box Brownie Mk2 Captain Sunshine, to be such a man as he, and walk so pure between the earth and the sea. WPF Gallery Birdforum Gallery |
#30
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__________________
Adey http://www.birdforum.net/pp_gallery/...00/ppuser/1805 'Write when there is something you know: and not before: and not too damned much after' Ernest Hemingway |
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