Sarah Fox 
, Jul 29, 2010; 11:58 a.m.
At the risk of trying Les' patience (sorry, Les), I was wondering what a "natural" bokeh would be. By a "natural bokeh," I'm referring to the optical characteristics of the human eye. So I pulled out a +20 diopter optician's loupe (always sitting atop my computer) to defocus my eye (setting a very close-in focus) and peered through it at an LED light. The result is that my eye seems to have a neutral bokeh, as illustrated by the middle pattern (B) in this figure:
Unfortunately I wasn't doing this test with a completely "natural" eye. I've had laser vision correction, so who knows whether the curvature of my cornea is "natural." Besides that, I had a piece of artificial glass in front of it to achieve a close focus, and that would introduce spherical aberrations of its own. Being an older person, I had to use a lens to achieve close focus to do this test, because as eyes age, they lose the ability to accommodate -- much like a camera lens with a frozen focus ring. Only a younger person or a near-sighted older person can really answer my question without the introduction of any artificlal optical elements.
So here's what I'm wondering: If you are able to focus your eyes really closely without the use of any corrective lenses (contacts, glasses, magnifying glasses, loupes, close-up attachments, etc.), and if you are able to look at a defocused image of a tiny light source (e.g. an LED) in the badkground (well beyond your point of focus), what does it look like -- A, B, or C? Hint: this will work much better and provide better insight into what is a "natural" bokeh if you can do it in a darkened room, allowing your pupils to dilate a bit. Also, don't do this with an LED flashlight (too bright). It's much better if it's an indicator light on some piece of equipment in the room.
Besides telling me this (whether you see A, B, or C), could you please indicate whether you could achieve a close focus (1) because you are blessed by being young and could just do it or because (2) you're near-sighted and simply had to remove your glasses.
Also feel free to participate even if you're like me and can't really provide any "natural" answers. I'll start:
I see pattern B using a +20 diopter optician's loupe. I'm old, normal-visioned, but with laser vision correction.
Thanks for participating! Should be fun to see the answers. :-)
Matt Laur 
, Jul 29, 2010; 12:08 p.m.
I'm getting a "B" as well, Sarah, but also just a bit of what I'd describe as some longitudinal smearing and perhaps just a whiff of "C." This was me focusing (unaided, with only one eye open - to avoid confusingly doubling the LED via parallax) at an object about 5 inches away. The LED was placed just to the side of that object, and perhaps at 24 inches.
My eyes are 46 years old. I'm glad they can still do this without giving me a headache. What's interesting is that the quality of my vision changes tangibly during ragweed season - which is now upon us. So, my test is being impacted by the always tricky Flora Bokeh.
Don Peterson , Jul 29, 2010; 12:20 p.m.
I see B with my glasses for both eyes and C without my glasses.
67 year old eyes wearing glasses for 60 years.
Sarah Fox , Jul 29, 2010; 12:26 p.m.
Don, without your glasses are you focused in front of or behind the LED? Are you nearsighted or farsighted?
The importance of this is that the bokeh pattern will reverse from A to C or C to A on opposite sides of the focal plane.
Sarah Fox , Jul 29, 2010; 12:28 p.m.
... and I'm jealous of both of you that you can still focus your eyes. Matt, I think my ability to accommodate my focus went from healthy to zero in only a few years. I just turned 49. :-(
Don Peterson , Jul 29, 2010; 12:33 p.m.
In front of the LED. I beleive I'm nearsighted.
Sarah Fox , Jul 29, 2010; 12:43 p.m.
Thanks, Don! :-)
So far 1 neutral bokeh with astigmatism and one creamy bokeh ;-) (I'm not counting myself, because I have unnatural bokeh.)
A note to everyone: If your eyeglasses magnify slightly, you're far-sighted. If your eyeglasses make everything smaller, you're near-sighted.
David Wilcoxson , Jul 30, 2010; 10:25 a.m.
I'm 52 and have been nearsighted all my life. Another vote for choice B.
Steve Gubin , Jul 30, 2010; 10:46 a.m.
Dear Sarah,
I attempted this test at my workplace yesterday afternoon. As it was the only small light source available, I utilized a laser pointer. The use of this device resulted in a temporary loss of vision in my left eye. While driving myself to an emergency appointment at the opthamologist, my utter lack of depth perception caused me to drive my car through the front entranceway of his office. Fortunately, no one was injured...although a rack of pamphlets outlining the benefits of Lasik surgery was badly crumpled.
I hope this information proves useful to you in your future studies of bokeh.
Cordially,
Steve Gubin
P.S. I never did see A, B, or C, but there is a fuzzy gray spot that floats in and out of my peripheral vision every 10 minutes or so.
Matt Laur , Jul 30, 2010; 10:51 a.m.
Steve. That's unfortunate. Next time you get a chance to pick up that laser pointer, check the little warning sticker on the side. You know, the one that says, "Do Not Point Laser Into Remaining Good Eye."
