Why do car 'wheel's appear to be travelling 'backwards' when driving forwards?
Answers:
In short, that effect is due to the relationship of light to the slow speed of the camera used to create the commercial and the speed at which the wheels are turning.
(much like disco balls which make people appear as if they are in slow motion)
it is an illusion
It is an optical sensation, or illusion.
Illusion effect!Wierd one at that.
Your eyes cannot process the reflected light fast enough. It only processes about a fraction. So it sees random snap shots and your brain smooths it out. Something depending on each snap shot it make more sence to your brain if it spins backwords,
Your point has been noted, from now on all car adverts are going to be shot with the car travelling in reverse, just for you.
a large hair dryer will be used to blow the occupants hair towards the back of the car to make it look like they are driving forwards,
happy now
my dad told me it has something to do with the difference between the time it takes to rotate one revolution and the camera speed. The wheel is really turning about 90% of the way around each time that the video camera captures it but when it's replayed it looks like its going backwards. I remember my dad using a poloroid camera to show me. He took a bicycle wheel and marked a line on the tire then he spun the wheel. Before the line would get back to the starting point he would take a picture. Then he would take another picture before it got around to where the last picture was. After about 10 times around he stack the poloroids up in order then flipped through them quickly and the mark on the wheel looked like it was going backwards!
A trick of the light. Your eyes can actually take in only so much at a time, and your brain has to process that information. You can't see an airplane propeller spinning at 3000 rpm, you just get a sense of a blurry space where the propeller is spinning.
At certain speeds, your eyes will tend to "catch" sight of a rotating object at key points. If those points appear at identical positions at the right times, it appears that the object is stationary. If the object rotates a little bit faster, we percieve that it rotates one direction, if the object slows down, we percieve it rotating in a different direction.
The effects become more pronounced in artificial lighting, as fluorescent lights have a very minor "flicker" at 60 cycles per second. The human eye can't normally percieve this in quality lights, but cheaper models may flicker more, and the amount of electricity from that wire being used also has an effect.
On television, you are limited to 24 frames per second, so the effect becomes even more pronounced on TV. Also, if you use a video recorder to record a TV, the signals rarely sync up, and thus you will percieve a flicker on the recorded set.
LCD and Plasma monitors do not work the same way, and will present a steady image if captured on video.
To be honest, i always thought that it was the hub caps (the silver things that cover your wheel) . I've seen ones that spin when the wheel moves and as it slows down they stop spinning. Maybe i'm wrong!
I know that wheels appear to be moving backwards in film because the wheel of the tire doesn't make one full rotation each frame so the wheel appears to be a little farther back. When this is all plays together in a film reel, it appears as though the wheels are moving backwards.
Stroboscopic effect to give it it's full name
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