What aperture f-stop are our eyes?

Kryptix

Kryptix

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Yes
I'm guessing about f/5.6?

Is there anyway I can adjust this? :thinking:
 
No, I don't believe in sunglasses/filters. Try looking at car headlights in the dark when wearing them, you'll never wear them again! Far too much sunglass-flare.
 
Oh and that still wouldn't change my depth of focus which is the effect I'm after... I want a 50L attached to my eyes!
 
your eye's change depending on how bright it is...

ie. smaller pupil when it's really bright, larger when it's dark
 
Apparently f/3.5 to f/8, depending on the light conditions.

The iris' adjustment to light is also apparently the only reflex that you can't override yourself, so I hear.
 
Kryptix said:
Oh and that still wouldn't change my depth of focus which is the effect I'm after... I want a 50L attached to my eyes!
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If you want a shorter field of focus you will have to wait until you are older.

I have continuously disappointed my optician who keeps insisting I will need glasses in two years time. He has said that for the last 16 years (8 eye tests)

Apparently my tiny pupils explain my ability to focus over such a large range, at 53 I'm noticing a small deterioration but not enough for glasses to be made to compensate.
 
colonel_mustard said:
Apparently f/3.5 to f/8, depending on the light conditions.

The iris' adjustment to light is also apparently the only reflex that you can't override yourself, so I hear.
Click to expand...
Thank-you! :)
 
f stop is focal length divided by aperture.

Focal length of an eye is about 22mm, aperture (or iris) varies depending on light from 2mm to 6mm (a rough guess).

So aperture range is about f11 to f3.6


Steve.
 
My depth of field is very narrow, about 25 cm from the end of my nose, then a sharp transition to blurriness. Probably something like f1.2
 
colonel_mustard said:
The iris' adjustment to light is also apparently the only reflex that you can't override yourself, so I hear.
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You've obviously never had hiccups then! :p

They eyes must have very large sensors. I say this because the image sizes are obviously quite big as I keep running out of storage space :(
 
Jamesbuk said:
Just as a side question then, what equivilant megapixel are our eyes? is it even possible to determine?
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it would be (approx) the area of image sensing cells at the back of our eyes, divided by the sizes of a rod and a cone detector cell added together, presumably...
 
itsdavedotnet said:
it would be (approx) the area of image sensing cells at the back of our eyes, divided by the sizes of a rod and a cone detector cell added together, presumably...
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OK, a bit of googling gets you 120 million Rods, 7 million cones, 1094 sq mm of retina.

Maths isn't my thing.
 
I'm glad somebody else has asked this, I've been pondering this for a couple of days now but thought it would be a stupid thread to post :LOL: 22mm is interesting, I thought they would be a bit wider than that. But then there are two of them I suppose
 
well that means 1094sq mm/ 127millions

= 1.094m/127 million

= 4.05 E-8

Doesn't look right some how
 
Jamesbuk said:
Just as a side question then, what equivilant megapixel are our eyes? is it even possible to determine?
Click to expand...

It's not about pixels, it's the processing software that counts - I have at least 200Tb of SDRAM running Medulla-Cortex-Pro 3.5
 
Resolution is a difficult one to answer. Only a small part of your vision is sharp, and that's the image that falls on the fovea. Everything else is blurry and out of focus, most detail you see is actually from memory. 50% of the

As the very centre of the fovea is only sensitive to colour and fails rapidly in darkness, if you want to see something as sharp as possible at night you should actually look slightly over to the side of it, so it falls on the rods around the fovea rather than on the fovea itself.

Have a look-see at this:
http://webvision.med.utah.edu/sretina.html

trapper501 said:
Apparently my tiny pupils explain my ability to focus over such a large range, at 53 I'm noticing a small deterioration but not enough for glasses to be made to compensate.
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The Beautiful South sang "Time takes its toll, but not on the eyes." They'd obviously never heard of age-related macular degeneration...
 
don't forget we have built in image stabilization :bonk:

rog
 
Yes, it is a real thread. I focused on my finger and tried to judge the DoF and I guessed at f/5.6. :)
 
If my eyes are at f5.6 I am sure they widen to f1 if certain females walk past :D:D
 
Depth of field is a function of focal length and aperture.

Basically, the larger the format (or image area projected by the lens) the larger the depth of field.

This is why large format cameras have a narrow depth of field at normal working apertures and point and shoot digitals with tiny sensors seem have huge depth of field regardless of aperture.

The eye probably has a similar range to a crop sensor camera with a 24mm lens fitted.



Steve.
 
Canon Bob said:
Nope...it's a function of magnification and aperture
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OK

Mathematically it's a function of aperture and focal length dictated by acceptable sharpness. So yes, magnification is more accurate.

My initial point was a reply to Kryptix about his suggestion that his eye had a DOF of f5.6 This is meaningless without knowing the image area.


Steve.
 
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Steve Smith said:
OK

Mathematically it's a function of aperture and focal length dictated by acceptable sharpness. So yes, magnification is more accurate.

My initial point was a reply to Kryptix about his suggestion that his eye had a DOF of f5.6 This is meaningless without knowing the image area.


Steve.
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(y)
 
It's estimated that for the young, the maximum aperture of the iris is about 7-8mm, as you get older this decreases, till around 5mm by 45-50. This is discussed quite a lot in astronomy circles, as for observational astronomy the exit pupil of the eyepiece (aperture of the objective/magnification of the optical system) is calculated to try and optimise the light passing into the eye (under ideal circumstances that is). And averted vision, not looking directly at a subject but rather looking to one side, whilst not an easy trick to master does indeed work brilliantly for dim objects.
 
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