Anyone know what causes this?

[QuaiOui]

The attached is four still frames from a video I took of my MA2s taking off. I shot the vid at 30 frames per second (I know...it should have been 60 :/)

Anyway, note how the props look like they're flying off in pieces in the top two images and the props look curved in all of them.

Of course, the props were fine, straight, and intact. Does anyone know what causes this optical illusion?

Thanks,
LivingstonView attachment 145539

As others have advised ot us rolling shutter. Some if the better editing software can correct this, depending upon how "distorted" it is.

Plus one developer of a post effect is currently working upon a beta version that they hope will be an even better "corrector".

 

[AheadAir]

Excellent demonstration and explanation of rolling shutter here:

 

[BethanyFerrell]

I learned about rolling shutter after restoring an ancient Folmer & Schwing Graflex model 3a, a 1907* SLR with cloth multi-slit curtain shutter. My lens had no iris so exposure was adjusted by two means: a knob to set the spring tension, and a key to wind the curtain to the desired slit width. You could bracket exposures by taking multiple shots, one slit width after another. Fastest shutter speed was 1/1000 second IIRC.

It's a fairly large-format camera, and film cost about $50/can in bulk back in the mid-1970s, so experimenting was kinda expensive. That was the only way to learn with something like that, so…
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* the latest patent date on mine was 1909