The Ansel Adams Fallacy: "True perspective depends only on the camera-to-subject distance"

We're just repeating our positions, and we're not likely to come to an agreement about them. Again, mine is that he said the right thing about the camera's role in perspective in a book about cameras and he said the right thing about the viewer's role in perspective in a book about prints. The subject of perspective in general was hardly more than a passing footnote in his famous trilogy. It was clearly not intended to be anything other than that, so having two brief observations about perspective appear in the specific books where they apply doesn't bother me at all. But I suppose he could have combined all three of them into one big volume, which might have encouraged readers to complete their reading instead of stopping short.

Another of my positions is that I never find much credence in what anyone (myself included) imagines a personage from the past would think or do today. Again, our positions might differ there as well.

I think perhaps we can agree to differ! 😉

I seriously think you are hung up on the subject of perspective. I think Adams was not hung up on it, but he knew all about it, and he said as much as he cared to say about it in his books about photography. There are plenty of other books that are all about perspective. People who are hung up on perspective should be reading those. Impugning Adams for not covering the subject in all its glory is just silly.

I revived this thread yesterday with a question, which I now repeat:

Despite all the discussion since, no-one has given a satisfactory answer.

Perhaps that means that everyone here now agrees that perspective distortions such as telephoto compression and wide-angle distortion depend on the viewer's position as well as the camera's position? 😉

That was never in doubt. It has always been well known that if you view a hyper wide angle shot from a very colse distance, you will see a more natural perspective.

I have illustrated above the geometrical theory of "natural" perspective. But the elephant in the room is asking why we should care about viewing a picture at such a distance and from a fixed point. Nobody ever views a painting or photograph in this way. The American academic in my PDF link used chopsticks to find the center of perspective and correct viewing distance, with one eye closed. On my last visit to the National Gallery in London nobody was using chopsticks to view the "Adoration of the Magi" by Sandro Botticelli from the centre of perspective and from the right distance.

Maybe it is just between to enjoy paintings and photographs with distorted perspective from a comfortable viewing distance.

Thank you for your concern. I am not hung up on the subject of perspective. I may be hung up on the many online tutorials that make claims such as in this one.

The title of the video is "Lens Compression Doesn't Exist - Here's Why". The video begins with a "dolly zoom" animation going from a wide-angle lens to a long telephoto while changing position so that the model stays the same size in the frame. The presenter then says "Now this animation may prove to you that lens compression does exist, but I actually want to show you that it is not the lens producing this look at all; it is the distance of the camera from the subject and from the background."

There are many other online tutorials that proceed along similar lines. They never mention the viewer's position relative to the centre of perspective. If they did, they could explain "lens compression" or "perspective compression" or "telephoto compression" with a simple zoom (without changing the camera position) without the need for a dolly zoom. He then proceeds to claim (without any evidence) that the compression effect is due to the "dolly" part of a dolly zoom, whereas it is really due to the zoom magnifying the image and causing the centre of perspective to move further and further away from the image.

[deleted]

[deleted]

I don't object to your objections about that YouTube video, or about any other misconceptions around perspective that are out there. I only object to the way you seemingly want to assign blame to Ansel Adams for those misconceptions to the point of naming a fallacy after him. The basic, correct information was in fact in at least two of his books. If you need to give that fallacy a name, there are much more appropriate choices.

Such as?

Maybe The Tom Axford Fallacy, to honor its debunker.

Thank you for the thought, but I have not been the first to debunk it by any means. I have just been rather more persistent than most. It needs someone highly respected in photography to say it's a fallacy before many photographers will listen. That someone is certainly not me!

If you read through the comments to some of the online tutorials that repeat the fallacy, there is often one or two voices who point out the error, but they just get told that they don't know what they are talking about and most don't bother arguing further.

[deleted]

Here's my question: aside from changing the position or focal point of the camera (and/or movements), how does one change the perspective of the photo for a given lens? That is, is it possible to move the camera and take another photo and get a photo with the same perspective?

HAND.

If you move the camera, then the photo will change. It is not the same photo. I think everyone agrees on that, it is not in dispute. I am not sure where this is going?

If I move closer, or further away to the building in the picture below, then the prospective effect on the building ( our subject) will change.

We can deduce this from Brunelleschi's experiment.

But for the scene as a whole, in the case below, you tell me. The angle of view of the camera lens remains the same and the perspective effect on the tiled floor remains the same as I move forward.

Thanks for your posts, although I confess to not being sure exactly what you are saying.

I rather like the following diagram from Jacopo Barozzi da Vignola (1583) in which a drawing or painting is imagined as transparent and the lines of sight are shown in more detail. When viewed from the centre of perspective, every point in the 2D image lines up exactly with the corresponding point on the 3D object. The position of the viewer's eye is critical.

It is obvious that if the viewer moves either closer to the image or further away, then the image will be seen with a different perspective in which points on the image cannot all line up with the corresponding points on the object.

- from Wikimedia

This diagram works equally well if we imagine that the image is a photograph on a transparent medium. The viewer needs to be at exactly the position of the camera when the photo was taken. It should then be possible to position the image so that everything in the image lines up exactly with the real scene behind it. The viewer's eye is then at the centre of perspective of the photograph.