How does perspective work in pictures?

Re:How does perspective work in pictures? by roywiggins on Wednesday March 02, 2022 @04:52PM (#30533711)

The mystery is "why can I view the world with my eyes and see a wide angle, straight lines, and "natural" perspective, but when I take pictures with a wide angle, everything looks "weird."

You can throw away the straight lines and shoot with a fisheye lens (no straight lines, wide angle, fairly natural depth), you can crop in (depth fine, but now I'm missing stuff around the edges), and you can shoot with a wide rectilinear lens (wide angle, straight lines, "exaggerated" perspective).

As far as I know, the answer is simply that your eyes aren't rectilinear but your brain fudges it to make straight lines seem straight when the image on our retina actually curves.

The effect is most prominent when standing in a small room. It's impossible to take a single picture of it that conveys what you want: a wide rectilinear lens will exaggerate how big the room is (and look weird around the edges), a "normal" rectilinear lens will be so cropped in that you can't see most of the room, and a fisheye lens will make all straight lines curve, especially around the edges. None of them really represent the visual experience of being in the room. Just look at how weird real-estate listings can get when they try to show you a picture of a small bathroom.

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Re:How does perspective work in pictures? by grumbel on Wednesday March 02, 2022 @05:53PM (#30534517)

The problem isn't taking the photo, but that the size you are viewing the photo at is simply too small and flat. Human field of view is somewhere around 200x130°, you are not going to capture that on a tiny flat bit of paper which might just be 40x30°. Reaching the 200° isn't even possible with a flat photo. You can try to make it aesthetically pleasing, but you can't make it accurate without making it bigger and curved.

When you enlarge the photo and display it at the field of view it was captured at, as you can do in VR, the whole problem disappears and the photo just looks like the real world. Use two cameras and it'll even be in 3D.

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Re:How does perspective work in pictures? by roywiggins on Wednesday March 02, 2022 @06:28PM (#30534944)

If you drop the requirement that you have a reasonably-sized flat image, you can get a perfect representation... as long as you stand in exactly one spot to view it (or throw it into VR).

If you intentionally use a nonlinear perspective like the Turner painting in the article, you can get an image that looks great flat, and still produces a wide angle of view and "natural" dense of depth with low perceived distortion, and will look fine from across the room or up close. It probably does a better job of recreating what it is like to be there than a mechanical linear perspective photograph. The only problem is you can't get images like that out of a camera.

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Re:How does perspective work in pictures? by c1ccccc1 on Wednesday March 02, 2022 @05:05PM (#30533860)

Probably a big part of it is that the high-resolution area of the retina is quite small. So in that small area, the perspective is close to perfect, and then we mentally stitch together a larger image by moving our eyes around. But the larger image that's stitched together is in the shape of a sphere rather than a flat surface, with each point on the sphere corresponding to a direction the eyes could be pointing.

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Re:How does perspective work in pictures? by twelvechairs on Wednesday March 02, 2022 @05:52PM (#30534510)

Yes. Also image aspect ratio and the relationship between horizontal and vertical is complex. Our eyes themselves move reasonably comfortably 15 degrees in all directions (maybe a little less up), but peripheral vision is greater in width than height and we are used to turning our heads to see objects in horizontal field of view more than vertical.

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Re:How does perspective work in pictures? by codeflo on Wednesday March 02, 2022 @07:29PM (#30535482)

> As far as I know, the answer is simply that your eyes aren't rectilinear

That's true, but not the problem. Think about this logically. The goal is to show the exact same color at the same angle. If you achieve that (possible with VR, also possible with a normal photo but for a tiny angle only), it doesn't matter how the eye or processing in the brain warps the image afterwards.

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