why when you see a car on TV spinning the wheels can you see the patterns of the alloy really slowly, then backwards.

is it something to do withthe camera "refresh rate", or something else?

 

ya mate,,,the wheel is strobing!

its when the wheel is turning at the same speed (or multipules of) the camera shutter speed!
remember with wheels, they have symmetrical patterns so it could be multipuls of these

 

cool. i thought it was something simple. I cant look at it, my eyes strain then i have to blink about 10 times to fix them.

thanks

 

what about when attending rolling roads?

whats the shutter speed of my eyes?

 

eyes dont have shutter speeds,, they scan for changes!

 

 

if the wheel is turning at 24 revolutions per second, the shutter speed on most cameras is going to be 24 frames per second so it will look static

as it speeds up, it will either lookl ike it's rotating forwards or backwards

it's the same as looking at a computer or telly screen through a camera, the refresh rate of teh camera is different to the refresh rate of the screen so you get them lines that go up and down it

 

Your brain can only process images at a certain rate also, so the same applies to us.

 

It's good when you watch f1 and from a very slow corner to top speed the writing on the wheels speeds up, then goes still, then it goes really fast and then gradually slows down again @ about 150 mph it's really cool to watch