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I suspect the illusion comes from assuming the picure is realistic, in the sense that there is a place where one could stand and perceive the scene as depicted.

I suspect the illusion comes from assuming the picure is realistic, in the sense that there is a place where one could stand and perceive the scene as depicted. In my experience, which is limited to phone cameras and the like, they seem to produce realistic images at short ranges, but a landscape picture looks much smaller and more distant than how the scene seems to me as I take it, unless I zoom in. That has me wondering if there is some geometry that would give realistic-looking pictures at all distances? Perhaps if the camera is sized such that the lens-to-sensor distance is about the same as the eye-to-picture distance when viewing the images? Another issue that I am wondering about comes from the fact that telescopes (and, I am assuming, telescopic lenses for photography) have an objective lens to produce an image that is much closer, and then an eyepiece (or whatever the equivalent is called in photography) to view that image. Does this have different perspective and foreshortening effects than a simple lens which merely casts an image directly on the sensor plane? To put it another way, for a given telescopic lens, is there, at least conceptually, an equivalent simple lens which would produce an identical image of any scene?

KineticLensman 6y ago
I use cameras practically and can’t quote the theory, but my understanding is as follows: > That has me wondering if there is some geometry that would give realistic-looking pictures at all distances? I don’t think so. Compared with wider angle lenses as in phones, camera telephoto lenses produce the compression effect when the nearer and further objects are relatively close to each other compared with their common distance to the camera. If you had three people at 5, 100 and 105 metres away the 5m one would probably be out of focus and look significantly larger than the two at 100 and 105m. A zoom lens allows the degree of compression to be changed, but the image changes as you zoom. > Another issue that I am wondering about comes from the fact that telescopes (and, I am assuming, telescopic lenses for photography) have an objective lens to produce an image that is much closer, and then an eyepiece (or whatever the equivalent is called in photography) to view that image. Cameras don’t have an eyepiece lens in the same way that telescopes and microscopes do. In DSLRs, there is a mirror that routes the light to the camera viewfinder. When a picture is taken, the mirror moves out of the way and the light from the lens directly hits the sensor. In mirrorless digital cameras, the viewfinder image is created electronically rather than optically from the sensor. Most serious camera 'lenses' in fact have multiple elements. By way of example, a Nikon 20-200 lens has the following: 21 elements in 18 groups (including 6 ED lens elements, 2 aspherical elements, 1 fluorite element, 1 SR lens element, elements with Nano Crystal and ARNEO coats, and a fluorine-coated front lens element) [0] [0] https://store.nikon.co.uk/nikkor-lenses-nikkor-z-lenses/nikkor-z-70-200mm-f-2.8-vr-s/JMA709DA/details#specificationstab https://store.nikon.co.uk/nikkor-lenses-nikkor-z-lenses/nikk...
- mannykannot 6y ago
  It is certainly true that a camera does not have the equivalent of a telescope's eyepiece lens (at least when capturing the picture), but I think one could say that in a telescope, the combination of eyepiece lens and the lens of the viewer's eye functions in the same way as a camera, by casting a real image on the sensor (the retina, in this case.)
bitcurious 6y ago
> In my experience, which is limited to phone cameras and the like, they seem to produce realistic images at short ranges, but a landscape picture looks much smaller and more distant than how the scene seems to me as I take it, unless I zoom in. That has me wondering if there is some geometry that would give realistic-looking pictures at all distances? Perhaps if the camera is sized such that the lens-to-sensor distance is about the same as the eye-to-picture distance when viewing the images? If you have access to camera with a manual hardware zoom, put it up to your right eye, keep your left eye open. Adjust the zoom on the camera until what you see with your right and lines up with what you see with your left. That’s the perspective that you see at. Do this with a few friends and you’ll find out that you all see at slightly different “zoom levels,” meaning there can’t be an out of the box universal “eyesight lens.”
vilhelm_s 6y ago
Telescopes etc are already designed to give the same perspective and foreshortening effects as a "simple" lens or a pinhole camera. There can be some imperfections (e.g. "barrel distortions"), but these are pretty small. Compared to a single lens, a fancy telephoto lens captures more light (producing a brighter image), it may blur the out-of-focus part of the picture more, and it has less chromatic aberration, but the perspective projection is the same. The perspective distortion comes for landscape photos are due to the field of view. So the absolute distance between lens and sensor doesn't matter, what matters is the ratio between that distance and the width of the sensor. As long as that ratio is the same as the ratio of the eye-to-picture distance and width of the picture, the perspectives will match. The problem is that if you are looking at a landscape with your bare eyes, you will look at a quite large field of view. To reproduce that field of view when looking at the picture, you probably need to print it several meters wide, and look at it from a meter away or so. If you take a photo with the same field of view but print it at a handheld size, it will look "too small" and the perspective will seem exaggerated.
ajuc 6y ago
> In my experience, which is limited to phone cameras and the like, they seem to produce realistic images at short ranges, but a landscape picture looks much smaller and more distant than how the scene seems to me as I take it, unless I zoom in. That's another issue, not caused by different lens or physics but by how our brains interprets what it sees. Our brains pick up and zoom on details subconsciously (and "compress" the uninteresting background) so you remember the details "bigger" than they are in reality. That's why medieval cities on paintings have often towers twice the height compared to a photo of the same view. Same thing happens when you look at the Moon and then make a photo of it (without zooming). You have to zoom 2 or 3 times before it looks as big as "in reality".

KineticLensman 6y ago

I use cameras practically and can’t quote the theory, but my understanding is as follows: > That has me wondering if there is some geometry that would give realistic-looking pictures at all distances? I don’t think so. Compared with wider angle lenses as in phones, camera telephoto lenses produce the compression effect when the nearer and further objects are relatively close to each other compared with their common distance to the camera. If you had three people at 5, 100 and 105 metres away the 5m one would probably be out of focus and look significantly larger than the two at 100 and 105m. A zoom lens allows the degree of compression to be changed, but the image changes as you zoom. > Another issue that I am wondering about comes from the fact that telescopes (and, I am assuming, telescopic lenses for photography) have an objective lens to produce an image that is much closer, and then an eyepiece (or whatever the equivalent is called in photography) to view that image. Cameras don’t have an eyepiece lens in the same way that telescopes and microscopes do. In DSLRs, there is a mirror that routes the light to the camera viewfinder. When a picture is taken, the mirror moves out of the way and the light from the lens directly hits the sensor. In mirrorless digital cameras, the viewfinder image is created electronically rather than optically from the sensor. Most serious camera 'lenses' in fact have multiple elements. By way of example, a Nikon 20-200 lens has the following: 21 elements in 18 groups (including 6 ED lens elements, 2 aspherical elements, 1 fluorite element, 1 SR lens element, elements with Nano Crystal and ARNEO coats, and a fluorine-coated front lens element) [0] [0] https://store.nikon.co.uk/nikkor-lenses-nikkor-z-lenses/nikkor-z-70-200mm-f-2.8-vr-s/JMA709DA/details#specificationstab https://store.nikon.co.uk/nikkor-lenses-nikkor-z-lenses/nikk...

mannykannot 6y ago
It is certainly true that a camera does not have the equivalent of a telescope's eyepiece lens (at least when capturing the picture), but I think one could say that in a telescope, the combination of eyepiece lens and the lens of the viewer's eye functions in the same way as a camera, by casting a real image on the sensor (the retina, in this case.)

bitcurious 6y ago

> In my experience, which is limited to phone cameras and the like, they seem to produce realistic images at short ranges, but a landscape picture looks much smaller and more distant than how the scene seems to me as I take it, unless I zoom in. That has me wondering if there is some geometry that would give realistic-looking pictures at all distances? Perhaps if the camera is sized such that the lens-to-sensor distance is about the same as the eye-to-picture distance when viewing the images? If you have access to camera with a manual hardware zoom, put it up to your right eye, keep your left eye open. Adjust the zoom on the camera until what you see with your right and lines up with what you see with your left. That’s the perspective that you see at. Do this with a few friends and you’ll find out that you all see at slightly different “zoom levels,” meaning there can’t be an out of the box universal “eyesight lens.”

vilhelm_s 6y ago

Telescopes etc are already designed to give the same perspective and foreshortening effects as a "simple" lens or a pinhole camera. There can be some imperfections (e.g. "barrel distortions"), but these are pretty small. Compared to a single lens, a fancy telephoto lens captures more light (producing a brighter image), it may blur the out-of-focus part of the picture more, and it has less chromatic aberration, but the perspective projection is the same. The perspective distortion comes for landscape photos are due to the field of view. So the absolute distance between lens and sensor doesn't matter, what matters is the ratio between that distance and the width of the sensor. As long as that ratio is the same as the ratio of the eye-to-picture distance and width of the picture, the perspectives will match. The problem is that if you are looking at a landscape with your bare eyes, you will look at a quite large field of view. To reproduce that field of view when looking at the picture, you probably need to print it several meters wide, and look at it from a meter away or so. If you take a photo with the same field of view but print it at a handheld size, it will look "too small" and the perspective will seem exaggerated.

ajuc 6y ago

> In my experience, which is limited to phone cameras and the like, they seem to produce realistic images at short ranges, but a landscape picture looks much smaller and more distant than how the scene seems to me as I take it, unless I zoom in. That's another issue, not caused by different lens or physics but by how our brains interprets what it sees. Our brains pick up and zoom on details subconsciously (and "compress" the uninteresting background) so you remember the details "bigger" than they are in reality. That's why medieval cities on paintings have often towers twice the height compared to a photo of the same view. Same thing happens when you look at the Moon and then make a photo of it (without zooming). You have to zoom 2 or 3 times before it looks as big as "in reality".