Stereo 3D filmmaking: the Complete Interactive Course

[Mathew Orman]

Originally Posted by Steve LaPierre

I understand that portion but if you are sitting back from the screen an appropriate distance wouldn't that large separation, 300 cm, be correct for that particular object's location/depth? I don't want to hijack this thread for this conversation and will hopefully gain some understanding from Lipton's book that will make this more clear to me, so no need to respond to my question. Thanks for your response and the original question of image produced for a particular screen size will be a better topic in your seven masters thread.

Yes,
you are getting closer to full understanding of human stereoscopic vision geometry.
The 65 mm parallax is a false assumption as human eyes are perspective cameras and not orthographic and the 65 mm vanishes to single point in perspective geometry. Correct stereoscopic projection geometry includes
vanishing point geometry and assures that the captured scene is observed at the same physical size and distance as the stereoscopic camera that had captured such scene regardless of screen size.

Mathew Orman

[Adam Stanislav]

Your first false assumption is that the rules that apply to viewing the actual 3D space apply to the projection of two views on a flat 2D screen. The rules are different for both.

The second false assumption is that the distance of the viewer from the screen is proportionate with the width of the screen. This is not true if for no other reason that not everyone sits in the back row, especially not in a crowded theater. Depending on the size of the theater, the persons sitting in the front row sit anywhere between 20 (quite common) to several hundred (rare but I have seen such theaters) times closer to the screen than the persons sitting way back. Additionally, the persons sitting at the side of the front row have a completely different view from the one person sitting in the center of the front row.

Your eyes must never diverge, we are just not biologically and physically suited for that.

You have to adjust the parallax based on the width of the screen. Either that or you somehow have to sculpt a real 3D image in actual 3D space, something we certainly do not know how to do. Maybe someday we will. But as long as we are projecting two separate views on a 2D screen, 3D video is dependent on the size (well, width) of the screen.

[Mathew Orman]

Your first false assumption is that the rules that apply to viewing the actual 3D space apply to the projection of two views on a flat 2D screen. The rules are different for both.

The second false assumption is that the distance of the viewer from the screen is proportionate with the width of the screen. This is not true if for no other reason that not everyone sits in the back row, especially not in a crowded theater. Depending on the size of the theater, the persons sitting in the front row sit anywhere between 20 (quite common) to several hundred (rare but I have seen such theaters) times closer to the screen than the persons sitting way back. Additionally, the persons sitting at the side of the front row have a completely different view from the one person sitting in the center of the front row.

Your eyes must never diverge, we are just not biologically and physically suited for that.

You have to adjust the parallax based on the width of the screen. Either that or you somehow have to sculpt a real 3D image in actual 3D space, something we certainly do not know how to do. Maybe someday we will. But as long as we are projecting two separate views on a 2D screen, 3D video is dependent on the size (well, width) of the screen. """"

I do not have to do anything.
The are no assumptions. It is strict geometry of viewing system.
In theaters there is only one seat that matches the view angle and stereo-window distance.

Mathew Orman

[Adam Stanislav]

Originally Posted by Mathew Orman

In theaters there is only one seat that matches the view angle and stereo-window distance.

And do you want to shoot 3D movies that you show to one person per theater? Maybe you do, maybe you do not.

But if you shoot movies to show to full theaters, as most filmmakers do, you need to deal with the parallax.

[Mathew Orman]

No,
in my theaters viewers have glasses that match their position geometry with projection geometry.
Most directors still shoot 2D with distorted perspective and that fallacy
continues into S3D shooting resulting to total gimmicks and zero realistic immersion in original scenes.

Mathew Orman

[Adam Stanislav]

Originally Posted by Mathew Orman

No,
in my theaters viewers have glasses that match their position geometry with projection geometry.

And what percentage of theaters do you own?

This is not about you. This is about reality.

[Mathew Orman]

Originally Posted by Adam Stanislav

And what percentage of theaters do you own?

This is not about you. This is about reality.

None,
I was referring to my new S3D vision system for which I've just filed a US patent application.
System which is at least 400% brighter , zero color distortion, zero ghosting, zero flicker and full realistic immersion on any size of a screen and 2D/S3D viewable simultaneously with equal quality regardless of seat position.

Mathew Orman

[Adam Stanislav]

Originally Posted by Steve LaPierre

I understand that portion but if you are sitting back from the screen an appropriate distance wouldn't that large separation, 300 cm, be correct for that particular object's location/depth?

There seems to be some confusion here, which stems from looking at the interaxial distance the way we perceive farther objects as smaller than nearer objects of the same size. This, however, is a completely separate issue.

A distant object appears smaller because the angle needed to see it is smaller than the angle needed to see the same object at a close distance. This is an optical illusion which makes the rails of a railroad connect at a certain distance. It has nothing to do with stereoscopy because the illusion also exists when you close one eye, or when you take a photograph with a single-lens (2D) camera.

In reality, those two rails never connect, they only appear to. You can ride the longest railroad in the world, which, as far as I know, is the Transsiberian Railway. You can board a train in Moscow and travel thousands of miles to Vladivostok, and the rails will keep a constant distance. This is the same as looking for a pot of gold at the end of the rainbow: There is no pot because there is no end of the rainbow. And two parallel lines never intersect even though they appear to.

So, when the two images of the same object are 65 mm apart, we look at them in parallel regardless of what the size of the screen is or how far the screen is. The distance will appear smaller but it is not smaller.

The easiest way to think about it is that two parallel lines appear to come closer and even intersect when we are looking at them, but they stay parallel when we are looking with them or through them. In other words, they appear to intersect when they are the object of observation but they stay parallel when they are the vehicle of observation.

I hope this makes it easier to see the difference and makes it clear that the 300 cm separation is never correct.