What's going on with this photo?????

[Sagar Pathak]

A good friend forwarded a series of pictures of his flight in a Stearman Biplane.  He was in the lead ship af a 3 ship formation.  In his series of photos it is clear that the prop is appearing distorted somehow, but I can't explain how or why it's showing up like this.  Does anyone know why this could be?  I know the guy and can vouch that the photo has not been altered.

Thanks!
~Sagar

[garphoto.com]

Apparently I am just confused by this - REALLY Its way beyond my learning curve.

- 

[Tbates]

Sagar,

I don't recall where I saw it but I believe if the photo was taken with a DV recorder that phenomenon can occur.  I've seen other untouched photos like that from DV recorders.

BTW, that's just a two bladed prop, if you look at the hub you can see what I mean.

Troy

[Dave Cibley]

Weirdness like this is usually caused by the shape of the shutter. Usually a two blade or two curtain shutter that, at fast speeds, never fully opens the whole frame but rather drags a "slit" across the frame. The prop moves as the slit passes across the frame so it's recorded in a different position as the slit moves over and exposes each pixel of the frame.

[bcradio]

LAX, that sounds like what's happening here.  Very interesting effect!

[El Guapo]

Exactly!  Nice call LAX.  If you look at older WWII aircraft pictures or later, you'll see the props have a twisted effect.  The only difference between those pictures and this one is that he probably used a shutterspeed of 1/2000 (not many cloth shutters can go faster than that.)  Older cameras were limited to around 1/500 hence them having a bit more blur.  The lower the shutterspeed, the less noticable the effect.

[GeoffS]

I have to admit I've never seen such a weird distortion (esp. the apparently disconnected prop blade!), but distortions caused by focal plane shutters are well-known.

Perhaps the "poster child" example is a photo of a racing car by Henri Lartigue.

Cheers,

Geoff S.

[futurshox]

I've seen this effect when I took a pic of a Catalina taxiing with my mobile phone; the props were all distorted in a similar fashion. Not sure if I still have the picture but if I can find it I will post it.

[PJB]

CMOS imagers which scan top to bottom will do this.
There's a perceptible lag between each of the scan lines, which are sequential, not interlaced like NTSC.
The results can be artistic when exploited.

[Bernardo Malfitano]

http://www.fencecheck.com/forums/index.php/topic,2584.msg77532.html#msg77532

[futurshox]

I still haven't found that Catalina photo but I've just taken this one, of a model wind turbine spinning merrily in my kitchen window. I took it with my phone again and here we have massive distortion! Sorry about the dodgy focus though...

[Jorgo]

So when the policeman asked me why I ignored the speed limit, I'll mention something about not seeing the sign due to Relativity, Warping of Time (at or near the Speed of Light), and something to do with Superman spinning the world backwards...

[atmosphotography]

Looks like Catastrophic failure to me!

[Hans Rolink]

So when the policeman asked me why I ignored the speed limit, I'll mention something about not seeing the sign due to Relativity, Warping of Time (at or near the Speed of Light), and something to do with Superman spinning the world backwards...

And then the copper will ask you what you do for a living, then call some nice but strong young men bringing a shirt with some very long sleeves after you answered them 

Hans.

[mcharlton]

I too would be curious to know what causes this. Most all of the photography I do is on models such as this. This prop is a 32" carbon fiber prop on a 157cc motor. I have taken pics where it seemed like the prop was almost wrapping around the fuse. This pic was taken with a 5D, shutter speed 4000, fstop 2.8. ISO 400.

This is my first post, but I have been lurking for a while. Great site.