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Stable Image
Greetings from New Zealand. It is wonderful to spend time with
Lisa's parents and to be in such a marvelous place. The past week has been
filled with dear friends, fantastic food, incredible scenery, and enough
adjectives to fill a thesaurus. How many different words can you use for
"wonderful"?
One of the highlights was a boat trip in their new boat. We went
to Sail Rock and then around the Hen and Chicks Islands. I added several birds
to my birding list and got some great photos of the geology. Taking the photos
was a challenge. Even with the image stabilization function on my camera, it was
still difficult to capture the image I wanted with the boat going up and down,
back and forth. That caused me to spend some time thinking about what an amazing
job out eyes and brain do at stabilizing images. To test that, you will need:
First, be sure that your test area is clear of any obstacles.
You will be walking quickly without being able to see where you are going, and
it is no fun to trip over a big rock in the middle of your experiment.
Pick a distant object as your focal point. Looking directly at
it, walk briskly towards it. OK, not much exciting about that. Everything looks
normal. Now go back to your starting place. This time, make your hand into a
fist. Open your fingers very slightly, so that your fingers form a tiny hole
that you can look through. You want the hole to be as small as possible, while
still letting you see the distant object through it.
Check your test area one last time for rocks, holes, little
brothers, and other obstacles you might trip over. Close one eye and hold your
fist up to the other, looking through the hole at the distant object. Trying to
focus on the object, walk quickly forward again. Do you notice a difference?
I found that walking slowly I could adjust my fist and head to
keep the image pretty well centered in my view, but as I walked faster and
faster, it got harder and harder. For an even better example, try this while
riding in a car (NOT while driving the car though!) The unexpected bumps give
you a much better idea of what a marvelous job your eyes and brain do at
stabilizing images.
How do they do that? Well, part if it is due to eye movements.
Although you may think that your eyes are pretty much sitting still when you
stare ahead, they are actually moving about quite a bit. Have someone stare at a
distant object and watch their eyes. You will see many tiny movements as their
eye focuses on different points of interest. Then try the same thing while
riding in a car, again having your friend stare at a distant object. Although
your friend may think that her eyes are not moving much, you will see them
zipping around as the car bounces.
Eye movement is only part of the process. You brain does an
incredible job of taking all the bits off image that you see and putting them
together into a picture of the world around you. Spread your fingers apart and
hold your hand in front of your face. Your hand and fingers block out much what
you see. Now move your hand up and down quickly. Your brain combines all the
different images to give you a clear picture of everything, though some part of
it is always blocked by your hand.
The distant object I am looking at now is a clock, which is
telling me that this experiment will be late getting out.
Have a wonder filled week.
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