Rolling Shutters

Did a little test today to see if my camera has a 'rolling shutter' approach. It's electronic, but I suppose it could still read the sensor a line at a time and give the same effect(?)

Anyway, having seen a number of photos of airplanes with 'bent' propellors (and a neat video) I thought I'd check out my camera (Olympus XZ-2).

I made a little test rig by taking a cylindrical sanding attachment for a drill, and drawing a '+'  on the end of it. Then I attached it to the drill and ran it at about 1200 RPM (at least, that's what it was rated at).

Some quick math: 1200 RPM is 20 rev/sec. Thinking about an individual 'radius line' (the line I drew on the end of the cylinder from the center to the outside edge) - for it to cover 1/4 of the area of the end of the drill during the time of the shutter being open, the drill would need to turn 1/4 turn . This would be 1/20 sec divided by 4 or 1/80 sec.

So I started at a shutter speed of  1/250 sec (meaning that the blurred line should cover about 1/3 of 1/4 of the disk) and based on the photo below this looks about right.

Then, moving up to 1/500th, 1/1000th and 1/2000th of a second respectively:

Didn't notice much evidence of curving lines and thought it was important that you know :-)

(A pretty good explanation-type video is here, And of course Wikipedia has an article.)