Sometimes What Your Sensors Indicate Is Wrong (Including your iPhone!)

This is a photo of my windshield wipers in action. Must be a howling wind. Look at how the blade is bent! (Note: the blade is straight! The iPhone camera is fooling us)

I'm parked in both pictures. In this one, the blade is not moving. The blade is correctly seen as straight, not curved. There is no wind. Not in either photo. Turns out that many camera phones save an image a line at a time. If something is in motion, it can appear curved because in the time it took to store the first line, the blade has moved. A picture doesn't lie. Really? How well do you understand the sensors you depend on?