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-   -   Jan 21, 2009: Digital Weird (http://cellar.org/showthread.php?t=19321)

Gravdigr 01-21-2009 10:43 PM

Quote:

Originally Posted by Wombat (Post 525005)
Nose cones don't cover the propeller blades. The blades come out the side of the nose cone. Which makes the photo plausibly real, not photoshopped.

Here are some pics of stationary propellers so you can see how the blades come out the side of the nose cone:

So it (the camera)manufactured parts of the prop that don't even exist?:3eye:

Wombat 01-21-2009 11:36 PM

Quote:

Originally Posted by Gravdigr (Post 525177)
So it (the camera)manufactured parts of the prop that don't even exist?:3eye:

I can't see any parts of the prop that don't exist, so I'm not sure what you are referring to. To me, every part of the picture looks consistent with a focal-plane shutter exposure of a moving object. Yes it is weird, but I think it's genuine :)

xoxoxoBruce 01-21-2009 11:58 PM

But how do you get a continuous blade, with two red tips, and no red nose cone in the middle?:confused:

Razzmatazz13 01-22-2009 12:44 AM

Quote:

Originally Posted by Sundae Girl (Post 524843)
Ooh, ooh! I want one of those, do you know where they sell them?

Actually...the last time I was camera shopping, they had cameras that claim to fix blotches on your face automatically (after auto finding your face in the frame of course) and other such craziness.

This one makes you skinnier:
http://www.reginalewis.com/2007/09/1...ounds-thinner/

barefoot serpent 01-22-2009 12:17 PM

lots more examples here and discussions of photon gating and Nyquist frequencies etc.

barefoot serpent 01-22-2009 12:23 PM

1 Attachment(s)
another example

spudcon 01-22-2009 03:45 PM

Moving objects in the same speed/direction as the scanner on a copy machine makes the object look longer. :-)

Wombat 01-22-2009 03:59 PM

Quote:

Originally Posted by xoxoxoBruce (Post 525182)
But how do you get a continuous blade, with two red tips, and no red nose cone in the middle?:confused:

Good question, lets see if we can work it out.

Looking at the pitch of the blades at the top-center of the picture (where there is least distortion), I think the propeller must be spinning clockwise as we look at it. That way the blades are pushing air towards the back of the plane.

If the shutter is a vertical slit that moves from right to left as we look at the picture, I think that explains the effect we see....

In the top-center of the picture, the blades and shutter pass in opposite directions when both are close to vertical, so we see straightish blades.

On the right of the picture, the tip of the blade passes the shutter first, then as the blade swings down through horizontal the shutter has moved slightly further left so we see the middle of the blade slightly further left than we saw the tip, and finally as the blade approaches the bottom of its swing the fast-moving blade tip overtakes the slower-moving shutter, and so we see the tip again slightly further to the left. The result: it looks like a double-tipped blade floating unattached in the air :3_eyes:

I'll let you figure out what's happening on the left of the picture yourself :D

HungLikeJesus 01-22-2009 06:17 PM

I agree. If the shutter is moving left to right, the propeller has to be spinning clockwise (from our POV). Because you can see the root of the propeller in the top but not the bottom, the smallest relative velocity between the shutter and propeller must occur there - so they're moving in the same direction at the top and the opposite direction at the bottom.

Elspode 01-22-2009 06:29 PM

But...if the plane was on a treadmill, and the iPhone was trying to take off, would the propeller blades appear at all?

Griff 01-22-2009 07:06 PM

Depends. Is the treadmill on a train approaching the speed of light?

SPUCK 01-23-2009 03:19 AM

No! But the train did leave the station going west.

Gravdigr 01-29-2009 06:33 AM

Quote:

Originally Posted by Wombat (Post 525180)
I can't see any parts of the prop that don't exist, so I'm not sure what you are referring to. To me, every part of the picture looks consistent with a focal-plane shutter exposure of a moving object. Yes it is weird, but I think it's genuine :)

I was talking more or less about the part of the prop that bolts to the hub. Where do the hub flanges disappear to, and where does the section of prop that magically appears to connect two seperate sections of prop where there should be hub flanges (for lack of the correct term) appear from?

And, to clarify, I'm not saying the pix are actually photoshopped. (I just thought the bs flag was cool) Just perpetuating the oft repeated cellar mantra. I've seen these type pix before, I just can't wrap my fragile little mind around the idea.:D

Anon. Y. Mouse 10-03-2009 03:42 PM

I believe you're seeing the reflection of the blades on the nose.

lumberjim 10-03-2009 09:00 PM

Anon E Mouse would have worked better


eta.....unless your 1st language es Espanol


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