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Old 10-09-2012, 11:04 PM   #1
Stevemoh
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Camera Setup for Human Eye

I need an accurate camera setup for the human eye in Max. Ive read 50mm in 3Ds max will do, but it looks incorrect. Ive read scientific studies that state the human eye is closer to 17mm -24mm. Can anyone shed light on this. I'm looking for accuracy in a court case.
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Old 10-10-2012, 12:02 AM   #2
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first - there is no solution to this problem, as long as you try to recreate it on a screen/print etc.

Focal length is always linked to the size of the sensor: 50mm refers to 35mm format (the sensor size) the same lens and focal setup with a double sized sensor results i a much wider angle. What changes in this case is the FOV (field of view)

now, we have a field of view of 160~170 - which would translate into ~1.5mm focal length on a 35mm camera. - now, that is a wild number, but right nonetheless, assuming you play it back on a hemispherical screen with the audience in the center.

you see where this is going - if you can determine the size of the screen you play it back, and the distance of the audience from the image plane, you can calculate the right focal length, which would then show the space as seen through a window, the size of the screen. (which is rather narrow and useless mostly - imagine 1m away from the screen, the screen 0.4m wide, its approx. the 50mm we started with)

if you followed me till here, and assuming i didn't do any wrong assumptions, we can agree that it is useless to try to recreate it scientifically, and best just stick to what looks good to our eye.

Last edited by damjan : 10-10-2012 at 12:05 AM.
 
Old 10-10-2012, 11:56 AM   #3
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hey Stevemoh, don't forget we have 50 mm "cameras", but two of them.
And a peripheral vision, where we concentrate our attention on the center of the frame.
This is impossible to recreate in a virtual camera.
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Old 10-10-2012, 12:29 PM   #4
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Also the human eye(s) flitter about very quickly, and the brain pieces together the "images" like a mosaic. It gives the impression that we are seeing in an instant far mor than we actually are. Add in the fact we have two eyes and the regions of good focus and the periferal poor focus (the brain again does a good job of filling in the blanks), and you can see it is near impossible to recreate what we "see" in a single image.

When you look at what the limited Mk-I Eyeball and the brain achieve into fooling us we are actually seeing more, and seeing it clearer than we actually are, its actually pretty amazing.
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Old 10-10-2012, 03:52 PM   #5
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Thanks for your response!

Let me explain a little more if I could. I am reviewing a case in which another studio set the camera up in LightWave at 50mm and another at 70mm. The purposes of these cameras are to depict the visual distance accurately.

The important thing to note is that the case being made is that the 70mm camera depicts the objects as they would appear to the naked eye.

**By using the 70mm lens, It's my assumption that they have made the objects appear much closer than at 50mm.

**To make matters worse there are scientific studies that approximate the human eye to be more in the neighborhood of 17mm.

When I set a camera up in Max at 17mm. While slightly more distorted it actually looks correct.

Needless to say I lack the full understanding to conclude what I suspect. Which is that the cameras in this situation are not admissible, they do not come close enough to accurately depict the human eye.

Therefore, they are misleading.
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Old 10-10-2012, 06:18 PM   #6
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Quote:
Which is that the cameras in this situation are not admissible, they do not come close enough to accurately depict the human eye.

Therefore, they are misleading.


exactly - and here is an easy example to see why:

take a picture frame (or a cardboard with a rectangular hole in the middle, whatever you like)
place it in front of you. (maybe 1 meter)
this represents the size of the imaging device, or print you want to use.

guess or calculate the "field of view" of what you see through the frame - and convert it to "mm" with this: http://kmp.bdimitrov.de/technology/fov.html

move the frame towards you, the FOV gets bigger, the mm smaller,
move it away, the opposite happens.
make the frame bigger, leave the distance the same (eg. projector instead of a screen) the FOV gets bigger, the mm smaller.. etc.

there is no point in trying to reproduce this the right way. it just cant work.
and i don't know what scientific studies are saying its 17mm or 50.. its either just wrong, or in a specific context)

Last edited by damjan : 10-10-2012 at 06:20 PM.
 
Old 10-10-2012, 06:18 PM   #7
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