My new flying rule - bring camera

"new_CFI" wrote in
:

I didn't have my camera the day I saw the 747 converted to water tanker
do a test drop...a waterfall from one end of the runway to the
other....it was awesome...all I have now is a memory of what it looked
like..can't show people a memory.

Now THERE's an idea!

Someone needs to invent a device that you can plug into your ear or nose and
it downloads your memory onto a stick that can be plugged into a hard drive
or printer for making 4x5's for $0.13!

What is the resolution of the human eye, anyway?

Judah writes:

What is the resolution of the human eye, anyway?

About 30 seconds of arc at best, under good viewing conditions and in
the zone of maximum visual acuity. To put that in aviation terms,
it's an ability to distinguish an object the size of a pie plate (nine
inches) from an altitude of 5000 feet, looking straight down.

--
Transpose mxsmanic and gmail to reach me by e-mail.

About 1 minute of angle if there is good light and contrast.



"Judah" wrote in message
. ..
| "new_CFI" wrote in
| :
|
| I didn't have my camera the day I saw the 747 converted
to water tanker
| do a test drop...a waterfall from one end of the runway
to the
| other....it was awesome...all I have now is a memory of
what it looked
| like..can't show people a memory.
|
| Now THERE's an idea!
|
| Someone needs to invent a device that you can plug into
your ear or nose and
| it downloads your memory onto a stick that can be plugged
into a hard drive
| or printer for making 4x5's for $0.13!
|
| What is the resolution of the human eye, anyway?

No, I mean in MegaPixels.

"Jim Macklin" wrote in news:POzWg.1483
$XX2.194@dukeread04:

About 1 minute of angle if there is good light and contrast.
"Judah" wrote in message
. ..
| What is the resolution of the human eye, anyway?

"Judah" wrote in message
. ..
No, I mean in MegaPixels.

That depends on both your estimate of angular resolution as well as your
estimate of the high-resolution field of view. Both vary considerably.

As an example, let's say that for the purpose of your question, we consider
only the field of view attributable to the fovea (the part of the eye that
has only cones, and no rods...this is considered the limit of
"high-resolution" vision...you can see a much wider field of view than this,
but without nearly the same detail as in the center of your vision). A
quick Google search turns up estimates of foveal field of view between 4
degrees and 15 degrees. So already we have quite a discrepancy of
estimates.

If we accept the 1 minute of angle estimate for angular resolution, that
gives us between 240 and 900 units of vision across the field of view. Call
those the equivalent of pixels, and assume a perfectly circular visual
reception, and you get between 45K and 636K "pixels". So in megapixels,
that's between 0.045 and 0.636.

That said, this is a pretty simplistic analysis of the equivalent in
megapixels of human vision. Human vision is different than digital vision
in a variety of ways, and a direct mapping such as shown above is leaving
out a lot of other factors that may affect total effective resolution. But
at the very least, this gives you a ballpark minimum starting point.

Also keep in mind that a digital camera may or may not have a lens capable
of resolving in perfect detail the total resolution available on the image
detector (usually a CCD). So you may have an 8MP camera, but when you look
at an image zoomed on a computer screen at a
one-display-pixel-per-image-pixel ratio, you may find a variety of artifacts
in the digital image.

So basically, human vision may be better than the theoretically calculated
resolution, while a digital camera may have less than the theoretically
calculated resolution. It's really hard to compare in a true
apples-to-apples way.

Pete

Google
Clarkvision Photography - Resolution of the Human Eye At any
one moment, you actually do not perceive that many pixels,
but your eye moves around the scene to see all the detail
you want. But the human eye ...
http://www.clarkvision.com/imagedeta...esolution.html -
12k - Cached - Similar pages


Visual Acuity and Digital Images It turns out that the human
eye only has a certain number of light detectors in it. ...
However, in digital images, the pixels or dots are square.
....
www.blaha.net/Main%20Visual%20Acuity.htm - 53k -
Cached - Similar pages


[DOC] http://clarkvision File Format: Microsoft Word - View
as HTML
The Human eye is able to function in bright sunlight
and view faint starlight, ... Visual acuity is defined as
1/a where a is the response in x/arc-minute. ...
http://www.nhn.ou.edu/~johnson/Educa...Range-2005.doc
- Similar pages


TECHNOLOGY CORNER ACUITY IN PRACTICE. A single human eye
sees roughly a 140-degree field ... Now, let's calculate the
distance between scanning line centers and pixel centers ...
http://www.tvtechnology.com/features...features.shtml
- 25k - Cached - Similar pages


Visual Acuity in Sensory Substitution for the Blind In
measuring the visual acuity of normal human vision, the eyes
move around ... with a typical horizontal resolution of 176
pixels for the PC camera input, ...
www.seeingwithsound.com/acuity.htm - Similar pages


HDTV displays: How good do they need to be? Thus, screens
don't have lines any more, only rows or columns of pixels.
.... The human visual acuity is 20/20 at any distance if the
height of the ...
broadcastengineering.com/hdtv-displays/ - 67k -
Cached - Similar pages


"Judah" wrote in message
. ..
| No, I mean in MegaPixels.
|
| "Jim Macklin" wrote
in news:POzWg.1483
| $XX2.194@dukeread04:
|
| About 1 minute of angle if there is good light and
contrast.
| "Judah" wrote in message
| . ..
| | What is the resolution of the human eye, anyway?

Bob Noel wrote:
yep - I've been kind of dumb these past few fall flights. Today
was yet another absolutely perfect flying day (today's flight is
the reason I own an airplane). I'm still kicking myself for
not having my camera.

There were some really beautiful high clouds that I
just can't describe. And the full moon rising over
the Atlantic was a sight!

--
Bob Noel
Looking for a sig the
lawyers will hate

I've taken a lot of pictures over the years and find that I
seldom refer to them. They don't capture the "spirit" of the moment, as
C.S. Lewis put it. The few times I wished I had my camera was when I
encountered an airplane like the one I was buiolding, as a few shots of
airframe details that don't get properly covered in the pans are a big
help.

Dan

wrote in message
oups.com...
I've taken a lot of pictures over the years and find that I
seldom refer to them. They don't capture the "spirit" of the moment, as
C.S. Lewis put it.

IMHO, that's missing the point. Please, bear with me.

I've taken thousands of pictures. Maybe even over ten thousand at this
point (but probably not twenty thousand...I'm not a professional, nor even
an avid hobbyist), now that digital photography came along (got my first
digital camera ten years ago).

Do I refer to most of those pictures after taking them? Nope. The vast
majority, I could delete forever and never notice. For the few that I do
refer to, do I do so to "capture the 'spirit' of the moment"? Nope...as you
and Lewis note, the picture rarely can perfectly put you back in the frame
of mind of the moment.

Though that said, the picture *can* at least remind you of a precious
moment. Your own memory is what recaptures the spirit, and the photo may be
meaningless to anyone else. But it's still a pleasurable experience to view
again for yourself.

More importantly (at least to me) is that the photo has artistic value in
and of itself. Most of the photos you take probably won't fall into this
category (unless you're an excellent and experienced photographer), but
that's not the point. All it takes is one photo every now and then for it
to be all worthwhile. And this is especially true with digital photography,
where a relatively small camera is capable of taking remarkably high-quality
photos, with no incremental cost associated with each photo, and with very
little inconvenience in having the camera with you.

This is why the "bring a camera" rule is such a good one. Today, it
requires very little trouble, and can produce great rewards. Most of the
time it won't, but it's easy insurance to cover those few moments when it
will.


And (just 'cause this post isn't long enough already ), here's my
thoughts on the digital-versus-film aspect of this issue:

Even when I was only shooting film, I did try to follow the philosophy that
"film is cheap". And relatively speaking it was. But it still cost
*something*, as did the processing. In addition, not doing my own
processing I was subject to the vagaries of the person who was doing it. I
tried nearly a dozen local processors before settling on one that could
consistently turn out photos that were of high quality, and even with them I
still occasionally got a print with a bit of lint on the negative. They'll
reprint the photo for free when that happens, but it's still a hassle to
have to go back and have them do it.

With a small digital camera, I get instant results, good-quality pictures,
no processing hassles or costs, and best of all it's easy to have the camera
with me at all times. I would never think of dragging my film camera around
with me all the time. It's more capable than the digital camera I use, but
it also is quite a bit larger, and I don't like carrying it without the
accessories (extra lens, flash, extra batteries, film, filters, etc) which
results in a pretty big load. With my digital camera, I put a fresh
rechargeable battery in it, drop it in my pocket or flight bag, and I don't
even notice it unless I need it.

So, even more so than used to be the case, digital photography has made it
even easier and convenient to always have a camera along.

(And yes, even before digital you could get 35mm "point-and-shoot" cameras,
but I never got the kind of results from those that I get with similar-sized
digital cameras today)

The few times I wished I had my camera was when I
encountered an airplane like the one I was buiolding, as a few shots of
airframe details that don't get properly covered in the pans are a big
help.

That's yet another great reason to have a camera along! If it's not a lot
of trouble to bring one, why not keep one with you at all times, just in
case?

Pete

This was taken last month on a breakfast flight to Leadville CO. No
camera...no pics.

http://home.pcisys.net/~ronlee/RV6A/...Sep06Small.jpg

Ron Lee

"Ron Lee" wrote in message
...
This was taken last month on a breakfast flight to Leadville CO. No
camera...no pics.

http://home.pcisys.net/~ronlee/RV6A/...Sep06Small.jpg

That is a great pic! You got a link for a high resolution version?

Just curious, but what reference points on the planes do the wingmen use for
lining up on lead? Root trailing edge to roll bar?
--
Jim in NC