1/8/2004: "Bent" propeller

This is a simple digital photograph of two windmills. But when the photographer looked at the resulting image, it became a mystery, because the propeller on the one mill is not bent like that at all.

Another image was taken:



...and now not only is the propeller bent, but there's a ghostly floating propeller as well! WTF? Are our digital cameras documenting a new kind of aura??

Nope. It turns out that this can happen with cheap digital cams. Some of them rather slowly "read" the image on their sensor, line by line. If the subject moves at the right speed, especially if the speed is close to the speed of the sensor "reading", the image captured can contain these kinds of artifacts. And so the result is not what was expected.

To show the same principle, a guy turned his flatbed scanner into a camera. It slowly "read" the image it was looking at, line by line. He took a picture of his garage door opening and closing while the image was being "taken", and here's what he got:

That's excellent!

Any link for these images, UT? I'm curious to know how the scanner was modified. Those things normally don't focus beyond a couple inches off the glass.

I experienced a "slow scan CCD" camera's effects while taking snapshots and driving down the interstate. The result: trees nearest to the road seem to lean in recognition of your speed.

The scanner camera guy has a really cool home page with lots of neat stuff:

http://www.sentex.net/~mwandel/index.html

If you haven't checked out the above web page yet do it NOW...this guy is a freaking evil genius!

Fasinating... I wonder what the window of error is that you have to hit in order for it not to be just plain blurry.

The propeller in that top picture looks like it was either by Dali or Burt Rutan.

I just noticed that those are Windchargers. They were made years ago in the little burg that I live in. If I'm not mistaken, they were among the first commercially available wind generators.

Hmmm, I smell a new hobby. Kudos, UT.

I was checking out his Ruins page and found a burnt castle from New Jersey and googled it. That lead me to this. Damn, I love the internet.