A couple days ago I posted this photo on Facebook because I thought it was interesting. Look at the reflected image of Justin Pawlak’s Roush Mustang in the water and you’ll see that the tail light reflections are the opposite of each other.
I already knew what caused this phenomenon, but I didn’t explain it very well in my caption, therefore I got a barrage of comments from nearly everyone on my friends list. I wrote: I’m guessing what happened here is that by the time the shutter curtain exposed half of the image the pulse of the LED tail lights turned off or on mid exposure. So, in the reflection the left-side light is on and the right-side one is off, while it is the opposite on the car. It’s crazy because I shot this at 1/6400th of a second. Stupid stuff like this still amazes me.
My buddy Loren Haleston made light of the situation: “Most LEDs pulse at around 1/200th, so anything faster will likely catch it mid pulse. What’s amazing is it seems like you somehow managed to capture the light before and after it had time to travel that extra distance to the puddle and reflect to your sensor. The speed of light travel 983 million feet per second, so to travel an extra six feet the reflection would only be 1/163,933,333th of a second behind the original source of light. Which is way faster than your shutter, so the only way this is possible is magic.”
Speedhunter Jordan Butters then responded in reply to my buddy Loren and explained it better than I would ever have: “Strong math skills, but that’s not it. It’s because the shutter curtain travels in a vertical motion; it’s picked up the lower light reflection and not the actual light – the only time calculation needed is Larry’s 1/6400 sec.”
What do you guys think happened?