Shallow d.o.f: our brain needs it

Lenny hit the point on the head, it's a personal POV. I've never try to say that our eyes have infinite DOF. It's a biological fact that they don't and that's not arguable. But what I'm trying to say is that our perception of what is in focus and what is not can play a role. Reality might not be what matter.

Another interesting example: if you don't already know, our brain has a "flip" function that reverses the image coming into our eyes, or else we just see everything upside down. This is not a result of the biological construct of our eyes (like a flip module) but it's a mental perception that we've developed. An experiment take an adult human and blindfold him for six months; when they took the blindfold off, the subject sees everything upside down, because his brain had adjusted. So sometimes how we think we see things is equally as important as what we can actually see.
 
Texanite said:
That might be true, but all these claims that our eyes naturally have infinite DOF and keep everything in focus at all times are completely 100% incorrect.
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I didnt say our eyes have infinite focus...i said the world...our envoironment... exists in complete focus. Of course our eyes make things look sharper or softer depending on what we focus on whether we use both of them or not.
 
Weston said:
I didnt say our eyes have infinite focus...i said the world...our envoironment... exists in complete focus.
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That's absurd.

The world is not "in focus" nor is it "out of focus". Focus is a function of the observer, NOT of the object itself.
 
If I may chime in (having a degree in psychology as well as film and studying brain structure)...

The eye is a piss-poor optical device. The only reason it works is because our brains have such great capacity for filtering.

Technically the eye has a very wide DoF. You can test this by holding a piece of paper at the end of your hand and reading the text, while reading another bit of text far away (like a billboard) with your peripheral vision.

The eye does do a bit of focusing, but most of the blurry out-of-focus look is done by the brain simply by not processing that stuff you're not looking at.

As for preference in film -- the audience doesn't give a poo. Hell, most people can't tell the difference between video and film -- even after you point it out.

The reason the eye-loves-shallow-DOF argument fails is that in reality we see everything that we want to see in perfect focus all the time simply by looking directly at it. A shallow-focus does not allow this because as your eye roams over the screen some parts will be in focus and some out of focus and you have no control over it -- therefore shallow DoF is very un-eye-like.

Shallow DoF is a stylistic choice that can be right or wrong for the choice of project. Personally I dislike shallow DoF because it treats the audience like morons who have to be forced what to pay attention to. However I have a couple projects coming up that stylistically require shallow DoF and hence I'm here lurking in this forum.
 
I disagree pmark23.
The eye is able to read both texts just because it moves 50 times a second in a manner that even you don't know it does. And it's able to toggle focus 50 times a second. As stated above our eyes have a focal aperture of f/2.25. the retina is 30mm wide. Our eye has a quite shallow DOF.

Once an infinite dof shot is projected, we will not be able to focus on any part of it because the whole set will be at the same distance... the screen distance.
So it is more natural to have one thing in focus than everything.
 
Texanite said:
That's absurd.

The world is not "in focus" nor is it "out of focus". Focus is a function of the observer, NOT of the object itself.
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you know what i mean. I'm saying ....if the world were photographed with a plenoptic lens it would all be in focus.

My comment was a response to someone saying an image of a background and a foreground in perfect focus was unrealistic because its impossible in life. Its not only a possiblity..its a reality. From a removed lensless perspective everything exists as it does when seen in a sharp focus. I didnt mean it was a function of the object itself.
 
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I think as an artist you need control over depth of field. A painter commands it, a photographer should embrace it, and videographers thirst for it. That's why these 35mm adapters exist. So Drink up!!!!
 
tex098 said:
I think as an artist you need control over depth of field. A painter commands it, a photographer should embrace it, and videographers thirst for it. That's why these 35mm adapters exist. So Drink up!!!!
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Even if i totally agree, the need for a shallower dof is not from an artistic view only. The shallow dof is a highway to the brain. shallow dof images are more logical to our brain. We see everything isolated, and a movie should do the same in order to be natural, apart large shots.
 
Not only are things behind or in front of you eyes' focus point blurry (because of your eyes' innately shallow DOF), they're also usually double-imaged due to your eyes pointing more inward or outward at the in-focus plane than is proper for the out-of-focus plane.

If I hold one hand in front of my face 10" away and the other 20" away, when I focus on either, I see a blurry double image of the other. Try it...

And no, I'm not hung over!
 
someday said:
a movie should do the same in order to be natural, apart large shots.
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Disagree. You're trying to take a dramatic tool and trying to define it as part of the human psyche. It's an impossible thing to prove and at best can only qualified as opinion. By the same token we can say that movies shouldn't be B&W either because that's not how the world is and human beings are uncomfortable watching something like that. Or we shouldn't do any color grading either because we're uncomfortable with weird colors that doesn't exist in real life.
 
What is impossible to prove? That the eye has a DOF and that a shallow dof in an image is most similar to how our eye works?
.
 
someday said:
What is impossible to prove? That the eye has a DOF and that a shallow dof in an image is most similar to how our eye works?
.
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Ok, but how do you prove what our brain perceives as "natural"? In other words, how will you show me that the way I see the world is the same as your? Some people are born with an inherent ability to visualize 3 dimensional objects and they become artists; can you honestly tell me that their brain see the world as we do, even though biologically they have eyes that work identical to ours?

Ever wonder if my red is your yellow?
 
Huy,
science has proven that every animal specie is standardized. We too are almost all the same. Of course there are exceptions.
In this thread i'm talking about the 99% of the humans, not about the exceptions.
 
someday said:
Huy,
science has proven that every animal specie is standardized. We too are almost all the same. Of course there are exceptions.
In this thread i'm talking about the 99% of the humans, not about the exceptions.
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I'm a biology major, and while 99% of our DNA are identical, the remaining 1% codes for important genetic variation across all humans. This is not the same as saying 99% of all humans are identical except for that 1%. Every single human being varies from each other, and this includes how our brain perceives the world. Artists are hardly the exception to the rules. Plus, just because our brain are constructed along similar lines doesn't mean that we all see things the same way. Genetics isn't an exact science, and there are countless pathways that remained to be discover.

Your argument brings back the old "nature vs. nurture" debate. Does our biology predetermines our ability to perceive the world? That is a question that hasn't yet been answered and I doubt it'll ever will be.
 
Huy, i agree totally with you.
In the case of the human sight, surely we are not identical, but very similar. The eye distance changes the 3D perception, other things may influence the color and light perception, but generally speaking the rules we are talking about in this thread apply to everybody.
 
GREAT!!!!! Now one of MY eyes just BURST INTO FLAMES AFTER READING EVERY POST IN THIS G@D D&MN THREAD! NOW I have NO DEPTH PERCEPTION!!


....oh, but the bokeh from my remaining left eye is QUITE nice. Hmmm. I think I might mount a Nikon 45mm into my open blackened bleeding socket. It's nice and compact.

:D
 
someday said:
I disagree pmark23.
The eye is able to read both texts just because it moves 50 times a second in a manner that even you don't know it does. And it's able to toggle focus 50 times a second.
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That is soooo wrong. Where are you getting your information from?
 
ciliary muscle are used to change the shape of our lens, thus changing focus. This in turn allows us to focus on distance objects as well as close up objects.
 
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