7D is faster than the speed of light??

I noticed something odd in these photos. These are adjacent shots from a high-speed sequence (posted in reverse order I think). Look at the scoreboard and the reflection of the scoreboard on the floor. In the first image the board is dark but you can still see the reflection in the floor.

Explanation?

- Keith -

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It's the frequency of the cycling of the lights in the digital scoreboard.
It happens quite frequently and often you will see only some parts of the numbers.
Someone else better qualified than me will probably be able to explain it better.

I don't know, I can't get past looking at that very scary person standing in front of those children.

Is it like when you exceed the max sync speed with a flash where the entire frame is not exposed at once?

The scoreboards LED's are blinking, and are not a solid. The picture was taken between the time that the LED's are showing color. Why the floor is still showing as if the sign is still lit up? Not sure. Maybe the shutter was faster than the light reflecting off the floor.. lol

Light travels at 186,000 mi/sec... So there is a difference in the distance light would travel between the sign and the sensor compared to the light reflecting off the floor. The distance is measurable and therefore the time it takes the light to reflect off the floor would take slightly longer.

Or has your photo been doctored, and this is just a joke?

There is no EXIF info on these pictures. What was the shutter speed and other exposure settings?

What was your shutter speed with these shots?

It probably has to do with aliasing, but I'd feel more comfortable saying that if I knew what the shutter speed was.

Edit: Zafar beat me to it.

Depending on the shutter speed the rolling shutter might have been the reason behind the reflections being there.

philwillmedia wrote in post #13869671
It's the frequency of the cycling of the lights in the digital scoreboard.
It happens quite frequently and often you will see only some parts of the numbers.
Someone else better qualified than me will probably be able to explain it better.

AbPho wrote in post #13869740
Depending on the shutter speed the rolling shutter might have been the reason behind the reflections being there.

There you have it.

At the time the area of the sensor corresponding to the board was uncovered, it was not illuminated; when the area corresponding to the reflection was uncovered, it was.

Maybe the frequency change with bouncing off the floor?

It's the Higgs Boson effect

At high shutter speeds, the exposure is made by an open slit that travels across the sensor. This is why you have a synch speed on your camera, at higher speeds the entire sensor is not exposed all at once.

So as the slit passed the scoreboard, it was on a dark phase of the 60 Hz flicker and appears dark. As the slit passed the floor, the scoreboard was back on power and you got a reflection.

From this I can tell that you were holding the camera horizontal.

xarqi wrote in post #13869800
There you have it.

At the time the area of the sensor corresponding to the board was uncovered, it was not illuminated; when the area corresponding to the reflection was uncovered, it was.

This is the conclusion I came to as well.

BTW, the photo was taken at ISO 3200, 1/640 sec f/2.8.

At 1/640, the shutter is a slit rolling from the bottom of the frame to the top. When the bottom was exposed, the LEDs were on. By the time the shutter got to the top of the frame, the LEDs were off.

You can also see this effect in videos (ex. cars with LED taillights). The LED's appear to be blinking or strobing in the video but look constant when viewed with your eyes in real life. The refresh cycles of the LED's don't match up exactly to the frame rate of the video resulting in flashing/strobing.

nice explanation folks!!