?Psychadelic from Chromatic Aberation?

I'm considering Chromatic Aberation caused by the human eye lense.
I think it's generally known that an uncorrected lense with a larger
aperature has more noticeable CA than one that is smaller.

The effects of drugs - like LSD - cause pupil dilation = that should
increase CA, hence LSD would cause fringes around visual objects.
What do you think?
(Druggies invited to post).
Ken

On Sat, 12 Nov 2011 11:56:05 -0800 (PST), "Ken S. Tucker"
wrote:

I'm considering Chromatic Aberation caused by the human eye lense.
I think it's generally known that an uncorrected lense with a larger
aperature has more noticeable CA than one that is smaller.

The eye has fairly significant CA, although the lens has little impact
on this, since the primary focusing element of the eye is the cornea.
Curiously, it is very difficult for a person to detect any chromatic
aberration, since the cornea's aspherocity does limit it somewhat, the
retina is not terribly sensitive to blue light (and has low resolution
in blue), and the brain processes out CA fringing. Where it is the
biggest problem is in designing ophthalmic instruments, since CA of
the eye affect the ability to focus light on the retina for
examination or therapeutic purposes, and limits the resolution of
instruments for imaging the retina.

You can (just) detect the CA of your eye if you look closely at a
small purple dot drawn on a sheet of paper. As you change its distance
from the eye, you'll see red and blue haloes that change their
characteristics. It's far from psychedelic, however.

On Nov 12, 4:26 pm, Chris L Peterson wrote:
On Sat, 12 Nov 2011 11:56:05 -0800 (PST), "Ken S. Tucker"

wrote:
I'm considering Chromatic Aberation caused by the human eye lense.
I think it's generally known that an uncorrected lense with a larger
aperature has more noticeable CA than one that is smaller.

The eye has fairly significant CA, although the lens has little impact
on this, since the primary focusing element of the eye is the cornea.
Curiously, it is very difficult for a person to detect any chromatic
aberration, since the cornea's aspherocity does limit it somewhat, the
retina is not terribly sensitive to blue light (and has low resolution
in blue), and the brain processes out CA fringing. Where it is the
biggest problem is in designing ophthalmic instruments, since CA of
the eye affect the ability to focus light on the retina for
examination or therapeutic purposes, and limits the resolution of
instruments for imaging the retina.

You can (just) detect the CA of your eye if you look closely at a
small purple dot drawn on a sheet of paper. As you change its distance
from the eye, you'll see red and blue haloes that change their
characteristics. It's far from psychedelic, however.

Is that experience with psychedics you're talking about, or something
deeper?
I find different focal lengths for differing frequencies.
Eg. Red - Blue can only get into focus at the same time, the other is
close but fuzzy.
Ken

On Sat, 12 Nov 2011 18:15:42 -0800 (PST), "Ken S. Tucker"
wrote:

I find different focal lengths for differing frequencies.
Eg. Red - Blue can only get into focus at the same time, the other is
close but fuzzy.

Yes, that is a good example of axial chromatic aberration. It is
sometimes used for visual effect (very annoyingly, IMO) on web pages
and advertising. In the natural world, it almost never shows up,
however.

The purple dot test demonstrates transverse chromatic aberration.
Again, you normally need to construct a special case to detect it. It
isn't something that typically shows up in normal vision conditions.

FWIW, only axial CA gets worse as the pupil dilates.

Chris L Peterson wrote in
:

On Sat, 12 Nov 2011 11:56:05 -0800 (PST), "Ken S. Tucker"
wrote:

I'm considering Chromatic Aberation caused by the human eye lense.
I think it's generally known that an uncorrected lense with a larger
aperature has more noticeable CA than one that is smaller.

The eye has fairly significant CA, although the lens has little impact
on this, since the primary focusing element of the eye is the cornea.
Curiously, it is very difficult for a person to detect any chromatic
aberration, since the cornea's aspherocity does limit it somewhat, the
retina is not terribly sensitive to blue light (and has low resolution
in blue), and the brain processes out CA fringing.

Some cameras do that now. I can see electronic eyepieces in the future
enabling this with refractors. If people haven't seen through Sony's
latest camera electronic viewfinders, check they out, they are coming
close to pure optical resolution.

There is more than CA at work when the pupil is dilated. Many myopic
spectacle wearers need a stronger prescription to drive safely at
night. Though I bet not many have night driving glasses in their car.
A mismatched prescription at night expands oncoming headlights into a
blinding glare. Which can easily mask a lot of badly-lit detail.
Things like road signs, pedestrians and cyclists. Let's be careful out
there, people.