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I was wondering about this the other day.
Why does the human eye not have c/a? I tried looking out of the corner of my eye towards a high-contrast edge, and I couldn't see any.
The eye has a simple design. It does not have high refractive index materials, no positive-negative doublets, or anything like that.
Anyone have an idea?
[quote name='backcountryskier' timestamp='1335384354' post='17766']
I was wondering about this the other day.
Why does the human eye not have c/a? I tried looking out of the corner of my eye towards a high-contrast edge, and I couldn't see any.
The eye has a simple design. It does not have high refractive index materials, no positive-negative doublets, or anything like that.
Anyone have an idea?
[/quote]
It may be to do with analogue post-processing, refined over many years!
CA correction is not so difficult, just think if the brain can invert/reverse the image from the retina in real time then it can do other tricks too. The brain does concentrate on the 'sweet spot', where CA will be lowest, sfter all
Best wishes
[quote name='backcountryskier' timestamp='1335384354' post='17766']
I was wondering about this the other day.
Why does the human eye not have c/a? I tried looking out of the corner of my eye towards a high-contrast edge, and I couldn't see any.
The eye has a simple design. It does not have high refractive index materials, no positive-negative doublets, or anything like that.
Anyone have an idea?
[/quote]
It may be to do with analogue post-processing, refined over many years!
CA correction is not so difficult, just think if the brain can invert/reverse the image from the retina in real time then it can do other tricks too. The brain does concentrate on the 'sweet spot', where CA will be lowest, sfter all
Best wishes
(sorry - double-hit key or something)
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In the eye the "sensor" isn't flat light a normal photographic lens, although what impact that has on lens behaviour I don't know.
Also, I believe you can see CA, but you have to force it. I have a black keyboard with white lettering on it. If I move really close to the keyboard and look at it, I can see blue/yellow fringing when semi-defocused. Yes, I can be that bored at work sometimes!
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
It does, just what you see is not what your eye "sees" <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt='  ' />. I.e. brains correct and create final image, it is not "direct translation" from the eye. Existence of longitudinal CA's is used in optometry. There is a "red-green" test, that allows to check if the refraction of the eye was corrected well enough (hypermetropes better sees in green color, myopes - in the red one).
A.
What is your firmware version? You may need an update! <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/rolleyes.gif' class='bbc_emoticon' alt='  ' />
feeling silly today - us seniors can be like that.
First I laughed of this, not mockingly, but cause it's such a photo-geeky thing to ask, and I've thought about it before myself <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt='  ' />
I have seen it though. I don't remember how, but I remember thinking about it when I noticed it.
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Yes, a slow day. I was gonna go skiing but it's raining here right now.
I can see blue/yellow fringing when semi-defocused
lo/ca, or bokeh fringing?
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[quote name='backcountryskier' timestamp='1335393925' post='17775']
Yes, a slow day. I was gonna go skiing but it's raining here right now.
I can see blue/yellow fringing when semi-defocused
lo/ca, or bokeh fringing?
[/quote]
Was afraid someone would ask that, and I can't remember! I'd repeat it later...
<a class="bbc_url" href="http://snowporing.deviantart.com/">dA</a> Canon 7D2, 7D, 5D2, 600D, 450D, 300D IR modified, 1D, EF-S 10-18, 15-85, EF 35/2, 85/1.8, 135/2, 70-300L, 100-400L, MP-E65, Zeiss 2/50, Sigma 150 macro, 120-300/2.8, Samyang 8mm fisheye, Olympus E-P1, Panasonic 20/1.7, Sony HX9V, Fuji X100.
[quote name='arv' timestamp='1335389372' post='17771']
It does, just what you see is not what your eye "sees" <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/smile.gif' class='bbc_emoticon' alt=' ' />. I.e. brains correct and create final image, it is not "direct translation" from the eye. Existence of longitudinal CA's is used in optometry. There is a "red-green" test, that allows to check if the refraction of the eye was corrected well enough (hypermetropes better sees in green color, myopes - in the red one).
A.
[/quote]
So we humans have a built-in CA correction then <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt='  ' />. That's indeed good... But why can we still see the CAs on image samples <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/tongue.gif' class='bbc_emoticon' alt=' ' />...
By the way, I wish digital sensors could mimic the human eye one day... A concave image sensor... Would'n that be great <img src='http://forum.photozone.de/public/style_emoticons/<#EMO_DIR#>/biggrin.gif' class='bbc_emoticon' alt=' ' />...
Serkan
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