what aperture do our eyes see at ?

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I'm pretty sure I've read that our eyes can have up to like a 24ev dynamic range, but that isn't all at once. They move and shift and readjust to get that much range. All at once it's somewhat less I believe.

But what about aperture ? When I try and test it out, by focusing on something close and then at the same time attempting to determine how focused something in a distant backround is, it is difficult to determine. I suspect my aperture is like F/8. :smile:

Any science on this aspect ?

Thanks,
floyd
 
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I wonder how it would be with eyes at f1.2.... :eek:

Interesting quesiton though. I'll subscribe to this thread for updates :smile:
 
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Due to the fact that our eyes are constantly adapting to focus and light maybe it would be better to think in terms of ISO range first then consider aperture and shutter speed combination?

http://www.pixiq.com/article/eyes-vs-cameras
Quote:
So, for the sake of argument, let's say that the minimum ISO of our eyes, on a bright sunny day, is ISO 25. Why 25? Because that's the lowest-ISO film that's currently in use, with the least grain and the highest quality around. If the lowest ISO of our eyes is 25, and our eyes are 600 times more sensitive in the dark, that means that the maximum ISO of the human eye would land somewhere around ISO 15,000 or so. If you choose ISO 100 as our base ISO for the human eye (which is equally fair, considering that we're comparing eyes to digital cameras, and most digital SLRs these days start at ISO 100) - our maximum ISO is around 60,000.
When we consider that the highest-ISO cameras (Like the Nikon D3S) can take photos at up to ISO 102,000 (see an example set of pictures at different ISOs over at The Imaging Resource), it becomes clear that our built-in technology is starting to lag behind what the camera manufacturers are cooking up!
 
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But what about aperture ? When I try and test it out, by focusing on something close and then at the same time attempting to determine how focused something in a distant backround is, it is difficult to determine. I suspect my aperture is like F/8. :smile:
First of all, the aperture is variable. Our eyes have these things called "pupils" that can be fairly large when it's dark, and fairly small when it's light. It works a bit like the aperture control on a camera.

Second of all, the aperture is variable. Remember that aperture is measured as pupil opening over focal length and although our eyes have only a single lens in a fixed position, the curve of it can be adjusted (take that, Nikon!) and as such the focal length can be adjusted.

However, aperture control is only there for exposure purposes. Depth of field is nearly irrelevant as auto focus is real-time and always picks the right location :smile:
 
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A young person's pupils can open up to 7mm and older people's pupils can open up to 5mm in extreme darkness. With as much light polution as most of us have our eyes rarely open up that much. In bright daylight our eye close down to around 1mm.

The focal length of the human eye is equivallent to 17mm ~22mm. That means that at best we see at F2.8 for younger eyes and F4 for older eyes in the dark and F16-F22 in bright daylight.
 
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Isn't that focusing, not changing focal length?
I don't believe there's a direct and perfect analogy between the focal length of a camera lens and the eye's equivalent, even if the focal length of the eye is a measurable quantity. This is because of the absolutely integral role the brain plays in processing and interpreting the information sent to it from the eye.

The brain is like an infinitely more subtle, sensitive and complex sensor, and we know for example how different sensors can affect the perceived focal length of a lens.
 
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Due to the fact that our eyes are constantly adapting to focus and light maybe it would be better to think in terms of ISO range first then consider aperture and shutter speed combination?

http://www.pixiq.com/article/eyes-vs-cameras
Quote:
So, for the sake of argument, let's say that the minimum ISO of our eyes, on a bright sunny day, is ISO 25. Why 25? Because that's the lowest-ISO film that's currently in use, with the least grain and the highest quality around. If the lowest ISO of our eyes is 25, and our eyes are 600 times more sensitive in the dark, that means that the maximum ISO of the human eye would land somewhere around ISO 15,000 or so. If you choose ISO 100 as our base ISO for the human eye (which is equally fair, considering that we're comparing eyes to digital cameras, and most digital SLRs these days start at ISO 100) - our maximum ISO is around 60,000.
When we consider that the highest-ISO cameras (Like the Nikon D3S) can take photos at up to ISO 102,000 (see an example set of pictures at different ISOs over at The Imaging Resource), it becomes clear that our built-in technology is starting to lag behind what the camera manufacturers are cooking up!
Maybe I just didn't get enough sleep, but isn't that article completely wrong? ISO doubles every time sensitivity doubles, that's what a stop is about, so ISO 15,000 is only somewhere in the range of 10.5 times. Given the D3S example, the max ISO of 102,000 is only 10 times the base ISO 200. Getting the result for 6000 times the sensitivity of any ISO number is going to require doubling that number 6000 times, not just multiplying it by 6000..
 
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However, aperture control is only there for exposure purposes. Depth of field is nearly irrelevant as auto focus is real-time and always picks the right location :smile:
Well, the DOF is what I was interested in. I wonder when I am focused on some one thing, if I were a camera and can see the whole frame at the same time, what kind of focus would the backround have ?
 
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The focal length of the human eye is equivallent to 17mm ~22mm. That means that at best we see at F2.8 for younger eyes and F4 for older eyes in the dark and F16-F22 in bright daylight.
Now that sounds pretty scientific and a plausible answer to my question. Thanks.

Not sure how I can make use of this great info, but it's still good to know. :smile:
 
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Well, the DOF is what I was interested in. I wonder when I am focused on some one thing, if I were a camera and can see the whole frame at the same time, what kind of focus would the backround have ?
Only the central 1 or 2 degrees of your field of view is actually in focus; your eyes move that around so your brain can fill in the illusion of everything being in focus...
 
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Only the central 1 or 2 degrees of your field of view is actually in focus; your eyes move that around so your brain can fill in the illusion of everything being in focus...
I started to reply to you, thinking you were way off base. My vision goes a lot wider than a few degrees. But then I decided to think about it and test it for a bit. Yea you are right. I guess because the eyes are in front of our heads, If I don't move my eyes or head at all, it's actually very little ( not much more than the size of my laptop screen, that I can keep in focus at one time.

Thanks !!
 
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I have a square floater in my eye that looks exactly like a single point AF of the CAM3500. I've had it since day one and it used to annoy me, but now it's kinda cool. It "follows" wherever I look, kinda like a single point AF-C trying to track a flying bird. I had it checked by my doctor and he said don't worry about it son.
 
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I don't believe there's a direct and perfect analogy between the focal length of a camera lens and the eye's equivalent, even if the focal length of the eye is a measurable quantity. This is because of the absolutely integral role the brain plays in processing and interpreting the information sent to it from the eye.

The brain is like an infinitely more subtle, sensitive and complex sensor, and we know for example how different sensors can affect the perceived focal length of a lens.
Sure we can concentrate on more or less of what's in the visual field, but that doesn't change the physical characteristics of the eye. FWIW looking up the focal length of the eye it seems to have been measured at 17mm.
 
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