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Progressive Scan CCD readout

I make no secret of my disgust of my cell phone's built in camera. It's really bad.

But because it's bad means it can sometimes be very interesting. For example:

Notice how everything is leaning one direction, in particular the road sign? This image does not represent reality. Everything I photographed was perfectly straight. But because we were in a car moving at a very fast rate, the digital camera produced this image.

Why?

The digital camera starts reading data from the sensor by rows of columns: from upper-left to lower-right.

So, as we moved from right to left in the frame, the first thing the camera recorded was the sky above the barn and the last thing it recorded was the grass and the base of the sign. But by the time it got to reading that information, we had moved forward just a little bit.

This is a pretty pedestrian example of slow progressive scan. For something a bit more interesting, take a look at this photo on flickr:

http://www.flickr.com/photo_zoom.gne?id=8798593&size=m

The image comes courtesy of a blog entry on a similar type of photographic distortion due to focal-plane shutters. Worth a read.

http://maisonbisson.com/blog/post/10531/