View Full Version : Weird filming effect

Jimmy Macintosh
1st Sep 2010, 19:28
I don't normally post about videos but I saw this and it just looks fascinating.

Bizarre Effect: This is what happens when you record a plane's propellers with a cell phone. [VIDEO] (http://www.wimp.com/recordpropellers/)

I know it's the frequency of the props and the frequency of the recording, but it just looks bizarre.

Flying Serpent
1st Sep 2010, 19:52
I'd be worried if the aircraft I was in was shedding blades at that rate. Better have a ready supply.


1st Sep 2010, 20:01
I have no technical expertise in this area so I suppose I ought to keep my trap shut, but I frankly dont believe that's what happens when you film a propellor with a mobile phone. Has to be some trickery somewhere!

1st Sep 2010, 20:07
Perhaps it has something to do with the window.

tony draper
1st Sep 2010, 20:15
Just a strobing effect similar a they used to get on movie cameras,:)

1st Sep 2010, 20:16
If it's trickery it's well-done trickery. If you take a high speed still photo of a propeller in flight and there are red blade-alignment marks on the spinner it'll show the pitch angle of the blades, which, depending on the aircraft speed will be an eye popping degree out of zero pitch, probably half-ways to the feathered position. Also, the blades will appear to be bent backwards 15 or 20 degrees out of vertical. With the scimitar shaped blades on that -8 the effect would be even more pronounced because of the scimitar shape. I guess. :p

1st Sep 2010, 20:27

1st Sep 2010, 20:37
OK G-CPTN - knew I should keep my trap shut :)

Loose rivets
1st Sep 2010, 20:39
It has to be something to do with the procesing just downstream from the matrix.

My best guess is that information is being delayed and then reintroduced. Odd effect. Be interesting to compare with a true hi-def camera that can work much more quickly.

Desert Dingo
1st Sep 2010, 20:39
It is called "rolling shutter distortion"

(Link keeps getting edited for some reason - replace asterisks with '********')
Bugger - it does not like b l o g s p o t
or r o l l i n g - s h u t t e r - d i s
Stuff it! - just Google "camera shutter distortion"


1st Sep 2010, 21:46
That's the funny thing about this site.

On a lot of forums if you say bugger or bloody or bollocks etc., it gets asterisked out. On here it's b l o g s p o t etc..

1st Sep 2010, 22:08
Just shows the (severe) limitations of the cameras built into mobile phones. Beats me why they don't just build a phone into a decent DLSR. As Clarkson says "How hard can it be?"

1st Sep 2010, 22:16
What DD said.
It's the combined effect of strobing and scanning side to side or top to bottom.