citizenlouie
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As mentioned, it's simply said to me. I also mentioned, I'd like to know its empirical study as well, so I can't answer your question. I also would like to know the source of the study myself.
I don't know how fast exactly is our "human lens", but I do know it reacts faster than any camera we have at the moment (it's also something people simply said, I've yet to read any study on it). I think you misread my statement and perhaps due to the fact you don't know what I do know.
None of these are what I was discussing in the original post. Focus is focus, DoF of a given aperture is another issue. You can get very shallow DoF even with very small aperture, due to subject-to-focal plane distance, and you can get out of focus area even with small aperture. They're all separate issues, so don't mix them in this discussion.
I have some limited medical training, though not a neurologist nor an optometrist. But I am a photographer and I do know my focus, aperture, DoF, perspectives, exposure and stuff. Please focus on one issue at a time, though they can be somewhat interrelated, but it's not what I was talking about. We are purely talking about a very specific subject, which is aperture of human eye, in term of DoF (not exposure), when eyes are focused toward the infinite end, during a typical daylight condition (assuming the eyes are healthy). If you dragged more variables into this discussion (i.e., not ceteris paribus) then the condition would be very different indeed, and probably too complex for the sake of this discussion.
I am pretty sure I said 35mm format (as oppose to 4/3 format), not 35mm Focal Length. Please do not change the subject. And that's the reason I also discussed 43mm "focal length" in the following paragraph, hoping some readers would at least catch the mistake when they read on. And I do mean DoF, not field of view. Some people's field of view are closer to 35mm (in 35mm format), and some are closer to 50mm (in 35mm format).
Do read the condition in which the argument is set. Any logical argument must be set in a prescribed premise before any conclusion could be reached, and I did set my premises very specifically (and some are implied, which I thought there was no need to elaborate). How can we come up with a logical conclusion if you keep change the rules of the game?
I also avoided talking too technical about 43mm focal length issue, precisely because I don't want to drag the perspective vs field of view argument into the equation.... Most people on DPR already have trouble understanding a given aperture's equivalent DoF and equivalent exposure between 35mm format and 4/3 format.... Perspective vs field of view can be even more confusing. Let's keep the argument simple: just human eyes' theoretical aperture. The Wiki article you mentioned also said something, which I also questioned in my original post, there can be too many variables, so a precise focal length and therefore aperture value (since it's calculation is depended on focal length) is very difficult to pinpoint. Wiki article mentioned the eye is liquid filled, and I did mention retina is curved and optical nerve (which translate image to our brain to process) is not in the exact center of the eye. With that said, you should already know I've been trying to say they're all obstacles to figure out the actual aperture of human eyes (and our retina isn't flat like a sensor, and our eyes aren't glass lenses, and our eyes' dynamic range is vastly superior than current sensor technology). Not to mention people's rods and cones arrangements are different, therefore, vision is an interpreted reality. You don't have to be a doctor to know this. As most modern artists know, reality is a subjective interpretation made by our brains.
The entire argument about what's human's natural aperture only needs an approximation, for our own reference when creating art. They don't need to be scientifically precise (though it's pretty mind-intriguing I must say, if we could find it out). And who said you must shoot at the same aperture and focal length that represent your eyes see? If that's so, why create wide angle lenses which give wide angle perspective or telephoto lenses that create compression perspective? And why all these DoF control tools with our cameras? If that's the case, shouldn't you be shooting with a Holga? (Holga is fixed to 47mm focal length with f/8)
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