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Old 1st February 2019
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Bikie John Bikie John is offline
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Re: Correcting perspective

Thanks for the comments. Derek, that's a useful comment about increasing the canvas size in PS. It always surprises me how much you seem to need.

The problem as I see it is that all the perspective corrections, stretches and so on is that they are applied uniformly so in the example the squares at the top are the same size as the squares at the bottom. This shows that it is a really neat projection, but I think this is what makes buildings look unnatural - we expect the top storeys to be smaller because they are further way.

Of course, because we also expect to see vertical verticals, this leads to a conflict - if all the bits stay the same shape the ones at the top are too tall. But a large part of lens design is about resolving conflicts like this and giving us a result that looks natural. The comes about because of deep-seated differences in the way we understand the world with our eyes and brains, and how a camera records it.

What I would like to try is a transform that straightens the verticals while letting the transverse lines get closer together with distance, as they do in the original. It might be horrible, we don't know until we see it, but I would still like to give it a try. I haven't figured out how to yet, though.

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