Approximating the human eye

[lampuiho]

DOF is the distance to the perfect focus that still remain clear.

From what I see, whether things still stay in focus has to do with whether the light that goes to the retina converge or appear to be converged (scattered but the scattered light is not sensed by another cell).

Yes, the size of your pupil can change the blur radius because of how much wider the light can go in and scatter to more area.

But I don't see how it makes more things stay in focus since light still get scattered no matter the size of your pupil.

 

[lampuiho]

He also doesn't understand what it means to dig up threads that have been dead for nearly 8 years and try to take a crap on its participants.

It's funny you said that when it's not called taking a crap on the participants.

THIS IS trying to take a crap on the participants, and was uncalled for: "Most of you must have failed high school biology"

Then please accept my apology. I did not see how stating something that is obvious to me is "taking a crap on the participants".

 

[Buckster]

DOF is the distance to the perfect focus that still remain clear.

From what I see, whether things still stay in focus has to do with whether the light that goes to the retina converge or appear to be converged (scattered but the scattered light is not sensed by another cell).

Yes, the size of your pupil can change the blur radius because of how much wider the light can go in and scatter to more area.

But I don't see how it makes more things stay in focus since light still get scattered no matter the size of your pupil.

Your misinformed opinion is just that, and largely incorrect because you have some ideas about what DOF is that are not supported by the science of optical physics.

Eyes and camera lenses have essentially the same physical characteristics and mechanical parts, and therefore work essentially in the same way. The lens is the lens in both. In the eye, the pupil acts as the camera lens aperture blades, both getting smaller to let in less light so we don't "overexpose" and be blinded and, like it or not, the physics of the diameter demand a difference in DOF in both eyes and camera lenses - it's physics - it doesn't change just because you can't seem to see it or figure it out any more than any other laws of physics. The eye's retina acts as the camera's sensor or film, where the lens and aperture blades/pupil focus the image.

Again, look at something close up and something far away. Note the difference in DOF (go read about DOF too, btw, because you still haven't got that straight). Do the pinhole experiment and note the difference in DOF between that surrogate pupil in front of your eye and your actual pupil, which will be much wider.

You're like a guy who's barged into a physics forum and is telling a group of amateur AND working physicists that there's no gravity on Mars because YOU haven't personally detected it and therefore can't seem to wrap your brain around it.

 

[Buckster]

It's funny you said that when it's not called taking a crap on the participants.

THIS IS trying to take a crap on the participants, and was uncalled for: "Most of you must have failed high school biology"

Then please accept my apology. I did not see how stating something that is obvious to me is "taking a crap on the participants".

How is it obvious to you that the participants failed high school biology? Oh, that's right, you've already demonstrated that you jump to conclusions that are not supported by scientific data or hard facts.

Chances are that every one of them that took high school biology passed, but feel free to present the ACTUAL EVIDENCE that they failed.

Oh, that's right... You don't HAVE any ACTUAL evidence to support your ad hom, do you? Awwww... Too bad...

 

[KmH]

File - Depth of field illustration.svg - Wikipedia, the free encyclopedia

When the pupil of an eye changes size, the focal ratio (f-number) of the eye changes.

Have you looked at this? - Entrance pupil - Wikipedia, the free encyclopedia

 

[Helen B]

DOF is the distance to the perfect focus that still remain clear.

From what I see, whether things still stay in focus has to do with whether the light that goes to the retina converge or appear to be converged (scattered but the scattered light is not sensed by another cell).

Yes, the size of your pupil can change the blur radius because of how much wider the light can go in and scatter to more area.

But I don't see how it makes more things stay in focus since light still get scattered no matter the size of your pupil.

DoF is not about what is in focus. You are correct that the size of the iris does not affect the point of focus (aberrations aside) but you appear to fail to understand that it is not relevant. DoF is about apparent focus, not actual focus, and the size of the iris does affect that. You also appear to misunderstand why things are out of focus - it is not scattering. You should try to learn some basic optics.

Apart from the optical theory, those of us with myopia can see it in practice. Without glasses, I can get aparrent focus further away in bright light than in dim light, and if you try using an artificial aperture immediately in front of your eye you can see more in focus.

 

[Buckster]

Apart from the optical theory, those of us with myopia can see it in practice. Without glasses, I can get aparrent focus further away in bright light than in dim light, and if you try using an artificial aperture immediately in front of your eye you can see more in focus.

EXACTLY what I learned at 10 years old, and the pinhole experiment.

 

[Helen B]

Apart from the optical theory, those of us with myopia can see it in practice. Without glasses, I can get aparrent focus further away in bright light than in dim light, and if you try using an artificial aperture immediately in front of your eye you can see more in focus.

EXACTLY what I learned at 10 years old, and the pinhole experiment.

And that is why we squint to improve focus when we aren't wearing glasses - the eyelids act as secondary pupils.

 

[deeky]

I think the problem (aside from dredging a rediculously old post) with finding the evidence is that in a captured photo, the image and dof is frozen, so we can move the selective focus of our eye around the photo to study the portions that are oof. When studying the oof portions of our sight, as soon as you try to look at the oof portions, your point of focus changes and that portion you are now trying to look at automatically comes into focus, making it appear that all portions are in focus. Silly brain - trying to focus on the center of our attention.

When I try to picture a study of dof in your own eyesight, I get the image of a dog chasing its own tail, just with your eyes (or someone on a bad acid trip watching the pink elephants fly around the room).

(Yes, portions of this is meant to be a bit synical.)

 

[Helen B]

I think that point was already covered in the thread, to be fair to the original participants. It's why those of us with myopia are more aware of DoF, I think: we can't focus distant things so we need ways of increasing our DoF if we aren't wearing corrective lenses to reduce our eye's power.