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If the human eye were a lens, what would it be?


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#1 Daniel Porto

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Posted 20 November 2008 - 05:33 AM

What type of lens and its characteristics best reflects how the human eye works?

I am assuming it would be a wide angle lens, but how wide?

How large would the DOF of field be? Orson Welles once said that one of the reasons for shooting Citizen Kane with a large DOF was because the human eye sees the world this way, however I don't find this to be true.

When I am reading a book and I focus on one word, I can read a only couple of words in the vicinity of this particular word that I have focused on. It is if our eye only focus' in a particular circle and everything around although can be seen, is not particularly in focus.

What frame markings would best represent what our eyes see? Academy? Super 35?

Do our eyes in general see in circles individually, but when both open combine to form a figure of 8 pattern, combining these two circles?

The reason why I am asking this question is because a lot of films that I have seen recently have used this 1st person perspective.
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#2 Simon Wyss

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Posted 20 November 2008 - 05:43 AM

Frankly, my dear, I don't give a damn. Let the eyes be our eyes and lenses be technical imitations, Imitation of Life.
http://www.imdb.com/title/tt0052918/
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#3 Michael LaVoie

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Posted 20 November 2008 - 10:30 AM

In 35mm cinematography, a 50mm lens is considered the "normal" lens. Meaning it's most approximate to human vision. In 16mm it's a 25mm.
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#4 Dan Goulder

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Posted 20 November 2008 - 10:46 AM

In 35mm cinematography, a 50mm lens is considered the "normal" lens. Meaning it's most approximate to human vision. In 16mm it's a 25mm.

Try standing next to a motion picture camera with a 50mm lens on it, and then look through the viewfinder. The difference in field of vision isn't even close.
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#5 Benson Marks

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Posted 20 November 2008 - 12:18 PM

What type of lens and its characteristics best reflects how the human eye works?

I am assuming it would be a wide angle lens, but how wide?

How large would the DOF of field be? Orson Welles once said that one of the reasons for shooting Citizen Kane with a large DOF was because the human eye sees the world this way, however I don't find this to be true.

When I am reading a book and I focus on one word, I can read a only couple of words in the vicinity of this particular word that I have focused on. It is if our eye only focus' in a particular circle and everything around although can be seen, is not particularly in focus.

What frame markings would best represent what our eyes see? Academy? Super 35?

Do our eyes in general see in circles individually, but when both open combine to form a figure of 8 pattern, combining these two circles?

The reason why I am asking this question is because a lot of films that I have seen recently have used this 1st person perspective.


Not even the best camera in the world can match that of the human eye. Our eyes are just too complex. For one, our eyes do have a lens. This lens, however, is impossible to imitate. For one, it is believed to be biconvex (A type of lens that most camera facilities don't seem to have, at least, from what I know). Second, the lens changes shape. To see objects that are closer, the lens has to thicken in order to focus on that object. To see objects that are far away, the lens flattens in order to focus on those objects.

As for DOF, do you happen to have a pair of glasses? I know I do and the DOF looks infinite to me.

Frame markings are a tough one. I'd assume open matte because our eyelids, in their normal state, tend to close a slight bit of the top and bottom of our eyes. It is only when our eyes are wide open that this isn't true.

Do our eyes see in circles or figure 8, you ask? Well, I'd say figure 8, but I don't really know.

Even with all this stuff I'm telling you, nothing comes close to human eyesight. First, our eyes are like having two cameras, not one. Second, film only captures half of what the human eye sees (Digital video captures less than that). Third, as I explained above, the lens of the human eye is just too complex.

So here's what I say, quit worrying about comparing cameras to our eyes. There is no camera that comes close to human eyesight, anyway. Just remember, 1st person perspective is another piece of the art of filmmaking, so be creative, and come up with an unusual way of presenting that perspective. That's all I can say about this topic.
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#6 Bob Hayes

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Posted 20 November 2008 - 12:42 PM

I would say it's an 12 mm lens with the center 35 mm being sharp and high resolution dropping off to pretty poor resolution on the periphery
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#7 Paul Bruening

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Posted 20 November 2008 - 12:51 PM

Try standing next to a motion picture camera with a 50mm lens on it, and then look through the viewfinder. The difference in field of vision isn't even close.


When we've had this discussion before it often broke into two camps: The field of view camp favoring wider lenses and the normal depth perspective camp favoring the traditional 50mm (2 inch for 35mm) length. As I recall a compromise of 35mm-40mm was sometimes reached. I favor spherical 50mm since I don't see any lens capable of getting a human's full field of view with anything close to normal human depth perspective anyway.
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#8 Michael LaVoie

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Posted 20 November 2008 - 01:23 PM

I'm not saying it makes sense but it was one of the first lessons in cinematography when I was in school. 50mm is considered "normal" meaning closest to human perception. Think about all the film still cameras that were sold back in the day with a 50mm already attached.
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#9 Stephen Williams

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Posted 20 November 2008 - 01:46 PM

I'm not saying it makes sense but it was one of the first lessons in cinematography when I was in school. 50mm is considered "normal" meaning closest to human perception. Think about all the film still cameras that were sold back in the day with a 50mm already attached.


Hi,

Sorry but every time I use a 50mm lens in 35mm I want a small tele, to me a normat lens for the format is a 32mm.

Using 1 eye matches the FOV of an 18mm pretty well, I don't have binoclar vision but I think Bob's idea of a 12mm using 2 eyes is about right.

Stephen
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#10 Jonathan Bowerbank

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Posted 20 November 2008 - 01:53 PM

Sorry but every time I use a 50mm lens in 35mm I want a small tele, to me a normat lens for the format is a 32mm.


I've read many DP's say something similar in AC mag. Usually it's closer to a 37mm that they equate with the DoF and physical perspective of the human eye.

I'm farsighted with an astigmatism, and when I'm not wearing contacts, my peripheral vision is even better. So I'm probably closer to a 20-25mm lens ;)
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#11 Dan Goulder

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Posted 20 November 2008 - 02:17 PM

when I'm not wearing contacts, my peripheral vision is even better.

In this business, it always helps to have contacts.
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#12 John Sprung

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Posted 20 November 2008 - 03:54 PM

What frame markings would best represent what our eyes see? Academy? Super 35?

We don't have frame lines, cameras do. We see what happens to be there, not carefully crafted compositions. (Unless we go to the movies or look at works of art, which in part is why we do those things.) There's no perpetual green "EXIT" sign just to the left and right of what we see. Real life ain't movies.

That being said, the human eye does have a simple single element biconvex lens. It's actually in a sense a zoom, because it changes focal lengths rather than moving back and forth to focus. When you're looking at the distant horizon, the focal length is about 25mm. It becomes more convex and shortens its focal length to look at closer objects. For instance, if you're half a meter from your computer screen, it would shorten from 25.0 to 23.8 mm. It has an iris with a range from roughly f/2 to f/8. The rest of the exposure and dynamic range issue is solved by the retina changing sensitivity, and the brain paying attention to the rods or cones depending on where it finds detail.

The human eye has lots of depth of field. It's the convergence of our two eyes that restricts our attention to a limited range of distances. Close one eye and hold an arm straight out in front of you with the thumb up. Shift your attention and rack focus between that thumb and an object at least several meters away. That shows you the DOF of your eye. Do that again with both eyes open, and you'll see that convergence is far more important and restricting than DOF.





-- J.S.
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#13 Leo Anthony Vale

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Posted 20 November 2008 - 04:26 PM

I'm not saying it makes sense but it was one of the first lessons in cinematography when I was in school. 50mm is considered "normal" meaning closest to human perception. Think about all the film still cameras that were sold back in the day with a 50mm already attached.


yet the still cameras have a larger frame than the cinecameras. So the 50mm still lens has an angle of veiw that is about the same as a 35mm cine lens.

The "normal" refers to the perspective not the viewing angle.
Books on amateur cinematography from the 30s mention that one shots with a 25mm lens on a 16mm camera, projects with a 50mm lens and views from a position halfway between the projector and screen, thus matching the perspective of the camera lens.

No one has mentioned that the back of the eye is not flat, but curved like the inside of a sphere.
The cameras that start to approach this condition are Widelux still cameras and three strip Cinerama cameras. These are curved in only one direction instead of being the inside of a hemisphere.
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#14 Daniel Porto

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Posted 20 November 2008 - 07:54 PM

THANKYOU

EVERYONE FOR YOUR FANTASTIC REPLIES!
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#15 Brian Rose

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Posted 21 November 2008 - 11:24 AM

I'd agree that you have to factor in aspect ratio as well. Considering binocular vision, we tend to see in widescreen. I'm no scientist, so this is purely observational, but I think that's one reason why 2.35 panavision has had such longevity. At least for me, it's the AR I enjoy the most, because it feels most compatible to my field of view.

Best,
BR
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#16 Brad Grimmett

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Posted 21 November 2008 - 07:48 PM

Using 1 eye matches the FOV of an 18mm pretty well, I don't have binoclar vision but I think Bob's idea of a 12mm using 2 eyes is about right.

Stephen

I would agree with this regarding FOV. But most 12mm lenses will have at least a little distortion, which we don't have with our eyes, and when you see a shot from a 12mm projected it doesn't seem like it matches our FOV. The truth is, our eyes are so different from lenses that it's almost pointless to make the comparison I think.
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#17 Leo Anthony Vale

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Posted 22 November 2008 - 02:44 PM

I would agree with this regarding FOV. But most 12mm lenses will have at least a little distortion, which we don't have with our eyes, and when you see a shot from a 12mm projected it doesn't seem like it matches our FOV. The truth is, our eyes are so different from lenses that it's almost pointless to make the comparison I think.


Again, the lack of distortion is due to the curved surface of the iris.
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#18 John Sprung

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Posted 24 November 2008 - 01:58 PM

The truth is, our eyes are so different from lenses that it's almost pointless to make the comparison I think.


Yes, exactly.




-- J.S.
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#19 Annie Wengenroth

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Posted 26 November 2008 - 01:04 AM

This one time I put on so much mascara, that my eyelashes were vignetting.
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#20 Chris Keth

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Posted 26 November 2008 - 01:06 AM

This one time I put on so much mascara, that my eyelashes were vignetting.


Did you use pancro to fix it?
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