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Bizarre pictures from cheap digital camera!!

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Gus Stangeland said:
Click to expand...
The scanning CCD reads one line at a time. Mechanical slit shutters would do a similar thing, but this is electronic.

Imagine the fan blade has two straight arms, red and blue.
  • As the CCD scans the top of the image, the blue blade tip is at 12oclock.
  • As the CCD scans successive rows, blue blade moves right (clockwise) toward 3oclock.
  • As blue blade gets lower and CCD scans it, red blade is rising on left toward 9oclock.
  • Blue blade tip disappears when it outruns the CCD that scans it.
  • Red blade tip continues to rotate while CCD scans it, until it scans the hub.
  • CCD scans below the hub, where it finds the blue blade again at 6oclock.
  • CCD scans the length of the blue blade, but since the blue blade is sweeping toward 9oclock, it drags quickly rightward and out of view.
Cut a thin slit in an opaque sheet of paper, then drag it downward slowly over the screen or a print of your bizarre images. For any single horizontal slice, the image should appear perfectly normal. It's just that the CCD doesn't record all slices at the same time.

--
[ e d @ h a l l e y . c c ] http://www.halley.cc/pix/
 
Chris Beney said:
A valid explanation for the C shape of the main blade has been
spelled out carefully on this thread, but no-one has yet explained
the C and S on the same picture other than simply saying 'it's the
scanning'.
Click to expand...
See my other posting on this thread; hope it helps. The separated secondary blade shape is seen at two positions, thanks to the scanning CCD. Once at both 12oclock-> 2oclock, and once at 3oclock to 7oclock. The gap is just because the blade was moving a bit faster than the CCD scan, and since the scan is only looking at one row at a time, the blade is out of view briefly.

--
[ e d @ h a l l e y . c c ] http://www.halley.cc/pix/
 
That camera make for some fun and curious pictures. As for actually being useful for photography I'd have to say that it appears to be a real POS.

Rob
 
RealPlupp said:
Here is my explanation about the S-shaped blade:

Pretend that the scanning goes from top to bottom. The scanning
reaches the blade that points to about 12 o'clock. As the scanning
moves down, the blade moves from 12 o'clock to 3 o'clock and at 3
o'clock the vertical speed of the blade is the biggest (and bigger
than the vertical speed of the scanning) wich results in the fact
that the blade leaves the scanner.
Click to expand...
Yes. And if one looks at the vertical movement of the scan and compares it with the rotation angle (and thus time) between the tip positions they are approximately consistent in all the pictures.

The scan from top to bottom for the whole picture would be about the time of one revolution of the shaft. Guessing at 1200 rpm (high wind we were told) then the camera scan was one twentieth of a second or 50milliseconds. A plausible figure.

I think I can now just about see it and am sufficienty satisfied not to try to reproduce it with some sort of paper or screen simulation.

 
Yes, see my posting above, I think it does make sense now. Thanks to all.
Chris Beney
Ed Halley said:
Chris Beney said:
A valid explanation for the C shape of the main blade has been
spelled out carefully on this thread, but no-one has yet explained
the C and S on the same picture other than simply saying 'it's the
scanning'.
Click to expand...
See my other posting on this thread; hope it helps. The separated
secondary blade shape is seen at two positions, thanks to the
scanning CCD. Once at both 12oclock-> 2oclock, and once at 3oclock
to 7oclock. The gap is just because the blade was moving a bit
faster than the CCD scan, and since the scan is only looking at one
row at a time, the blade is out of view briefly.
Click to expand...
 
It's long gone!
Wayne Larmon said:
Gus Stangeland said:
5. I cannot run any more tests because I returned the camera the
next day to get my refund. I did not want to wait until after
Christmas to hear "sorry, that was a special deal, you can't return
it". (As it was I had to plead with the manager).
Click to expand...
After stirring up this hornet's nest, would you consider going back
to Office Max and buying the camera back again so that you can do
more tests? Inquiring minds want to know.

Wayne Larmon
Click to expand...
 
Chris Beney said:
You said "Guessing at 1200 rpm (high
wind we were told) then the camera scan was one twentieth of a
second or 50milliseconds. A plausible figure."
Click to expand...
I think that is a little high on the rpm. This is a 6-foot propellor and these generators are wound to produce current at low rpms. I would guess more like 800 rpm.

When you say "camera scan" that's not the same as "shutter speed" is it? Because a shutter speed of 1/20 second would be WAY too long for this picture. Remember this was in very bright sunlight AND there is NO motion blur at all - amazing when you consider how fast the tips of the prop were moving.
I'm still confused by the extra floating prop.
Chris Beney said:
RealPlupp said:
Here is my explanation about the S-shaped blade:

Pretend that the scanning goes from top to bottom. The scanning
reaches the blade that points to about 12 o'clock. As the scanning
moves down, the blade moves from 12 o'clock to 3 o'clock and at 3
o'clock the vertical speed of the blade is the biggest (and bigger
than the vertical speed of the scanning) wich results in the fact
that the blade leaves the scanner.
Click to expand...
Yes. And if one looks at the vertical movement of the scan and
compares it with the rotation angle (and thus time) between the tip
positions they are approximately consistent in all the pictures.
The scan from top to bottom for the whole picture would be about
the time of one revolution of the shaft. Guessing at 1200 rpm (high
wind we were told) then the camera scan was one twentieth of a
second or 50milliseconds. A plausible figure.
I think I can now just about see it and am sufficienty satisfied
not to try to reproduce it with some sort of paper or screen
simulation.

Click to expand...
 
You blew it by returning the camera. It takes priceless pictures.

There is no doubt it would butcher any type of action shot, yielding some most interesting pictures. I might check with my local store, see if they have any left. Don F.

http://forums.dpreview.com/forums/read.asp?forum=1010&message=7139025
Rob Bell said:
That camera make for some fun and curious pictures. As for
actually being useful for photography I'd have to say that it
appears to be a real POS.

Rob
Click to expand...
--
http://www.DForbesRowanPhotos.OrangeCountyandSurrounding.PhotoShare.co.nz
D. F. R.
 
Looks like this camera is avoiding blurry pictures, while actually using a very long shutter time. If it takes the camera 1/10 sec to scan all lines, that would mean each line is only "exposed" for 1/10/480 = 1/4800 sec.!

So with this camera, moving doesn't make things blurry, but only makes them distorted.
 
Actually, per your formula, the shutter time would be 1/12000 sec. The original pictures from the camera were 1600x1200 pixels. I resized the pictures to 640x480 to better fit this forum.
**** Nagtegaal said:
Looks like this camera is avoiding blurry pictures, while actually
using a very long shutter time. If it takes the camera 1/10 sec to
scan all lines, that would mean each line is only "exposed" for
1/10/480 = 1/4800 sec.!

So with this camera, moving doesn't make things blurry, but only
makes them distorted.
Click to expand...
 
I have always wondered by digital cameras go to all the effort of incorporating a complex mechanical shutter. The camera is already super-smart with computer and firmware - why not just switch the incoming light to the CCD with an electronic switch?

Maybe it is because if you do, these are the results you will get! In order to capture EVERY pixel at exactly the same time (to avoid any kind of distortion due to movement) you MUST "expose" the entire CCD at once, which apparently is not possible to do electronically.
Could this be the case?
 
BillS said:
These images appear that thery were formed by a linear scanning
mechanism within the camera. For stationary objects, this would
not be apparent, but when there is motion there seem to be some
distortion.
A similar phenomina has been produced by Andrew Davidhazy of
Rochester Institute of Technology. He has built 'digital cameras'
from old hand scanners and various mechanical parts. He has
produced many bizarre effects which you can see at this site.
http://www.rit.edu/~andpph/travel-exhibit.html

Construction of this camera is described here:
http://www.rit.edu/~andpph/text-demo-scanner-cam.html

Bill
Click to expand...
--
Digital Deluxe Toolbox - Photoshop Actions for digital photographers:
http://www.2morrow.dk/75ppi/coolpix/actions/
 
Gus Stangeland said:
I have always wondered by digital cameras go to all the effort of
incorporating a complex mechanical shutter. The camera is already
super-smart with computer and firmware - why not just switch the
incoming light to the CCD with an electronic switch?
Maybe it is because if you do, these are the results you will get!
In order to capture EVERY pixel at exactly the same time (to avoid
any kind of distortion due to movement) you MUST "expose" the
entire CCD at once, which apparently is not possible to do
electronically.
Could this be the case?
Click to expand...
this is why most cameras have a buffer so the whole image can be exposed in one go and stored while the camera processes the picture,in this case it looks like the camera has no buffer so it processes the image live ,probably one line at a time
regards
Tony
 
Thanks for the illustration. This, combined with the no-buffer idea posted earlier, pretty much sums it up I think. The better cams have faster components, more buffer, better processors, and can't produce special effects like this. I still do not fully understand the floating blade, but I accept it.
RealPlupp said:
Chris Rake said:
Here's what's going on:



--
Chris Rake, Austin Texas
Personal Gallery and Central Texas Photo Guide
http://crakephoto.com
Click to expand...
--
Looking for my first Digicam (for about 500 €)
Click to expand...
--
http://www.DForbesRowanPhotos.OrangeCountyandSurrounding.PhotoShare.co.nz
D. F. R.
 
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