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silverJON

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Jonathan
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OK, so it's sort-of unrelated to photography, but it's not related enough to go into a topic forum.

I was wondering - when we see in low light, and our iris withdraws and makes our pupil bigger, does it reduce our visible depth of field?

Discuss.
 
Don't think so, our 'depth of field' is very good, as we have 2 eyes, I'm sure I read about it somewhere anyway :)
 
I don't think we have a true "DOF" due to the way that the brain processes the information from the eye. I think it's only a small amount of the central vision that has any real focus / detail. This is why macualr degeneration does so much damage to the vision compared to the actual size of the macular area.



**If I use enough big scientific words can I get a job with a Hair Shampoo company ??
 
I don't think so. I have naturally quite large pupils, and if anything, I am very slightly long sighted!
 
answer is yes
"ye canna beat the laws of physics, Jim"
but the saviour is the fact that whatever we look at (focus on!) is in focus, so DOF doesn't really come into play
It's only the centre of the eye that can see detail (and colour) anyway; the edges are better at low levels
hence, at night, look slightly to the side of the target and you can see it better - wierd but it works

Biology 101
 
The rules regarding "circles of confusion" which is the bit that determines DOF exists when light passes through any aperture so in theory yes. As previously stated however, between our auto-focus lenses and super-processor chip we can compensate pretty quickly.
 
Foveation, whereby the difference in photoreceptor density causes the centre of the image to be sharp and the edges to appear blurred (just lacking in detail), is not the effect I'm talking about - that's what a Lensbaby does and is replicable in Photoshop.

I mean literally depth of field - if you close one eye and look at two things that look adjacent but are at different distances from you, how out of focus is the one you're not focussed on, and how does light level affect this?

Optically, the only difference between the eye and a camera with prime lens is that the eye makes do with a simple meniscus lens because it's focussing the image onto the inside of a sphere (the retina), whereas a camera needs a series of lens elements because it has to focus the image onto a flat plane. I wonder if the problem of DOF is only introduced because the lens has to account for this flatness, and thus isn't present in the eye?

I'm a biomedical engineering student, so this is really interesting to me :)
 
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