Julesimages Posted January 27, 2014 Share Posted January 27, 2014 Anyone able to explain what has happened to the B's on the bus in this picture please? I don't understand why they aren't a blurred streak like the rest of the bus? I could understand one B at the end or beginning of a streak but not all those multiple B's! The exposure was 1/8th second at F4 Link to comment Share on other sites More sharing options...
Julesimages Posted January 27, 2014 Author Share Posted January 27, 2014 It's DR20BW Link to comment Share on other sites More sharing options...
Stokie Posted January 27, 2014 Share Posted January 27, 2014 Anyone able to explain what has happened to the B's on the bus in this picture please? I don't understand why they aren't a blurred streak like the rest of the bus? I could understand one B at the end or beginning of a streak but not all those multiple B's! The exposure was 1/8th second at F4 Because it was a cold night (if it had an R at the end)! Link to comment Share on other sites More sharing options...
spacecadet Posted January 27, 2014 Share Posted January 27, 2014 That's the LED destination board, probably showing the route number as well. Characters on an LED display are formed by successive illumination- one LED is lit up at any one time and it's only persistence of vision which makes them appear continuous. Photograph one with a shutter speed faster that about 1/60 and you will get a partial image. So he has captured successive scans of the same number during the long exposure. Link to comment Share on other sites More sharing options...
Ed Rooney Posted January 27, 2014 Share Posted January 27, 2014 Ah, that's simple. But first I'd like to explain to you about the Meaning of Life. . . . Link to comment Share on other sites More sharing options...
Niels Quist Posted January 27, 2014 Share Posted January 27, 2014 That's the LED destination board, probably showing the route number as well. Characters on an LED display are formed by successive illumination- one LED is lit up at any one time and it's only persistence of vision which makes them appear continuous. Photograph one with a shutter speed faster that about 1/60 and you will get a partial image. So he has captured successive scans of the same number during the long exposure. BBBBBBBBBBBBBBBBRAVO! Link to comment Share on other sites More sharing options...
StanRohrer Posted January 27, 2014 Share Posted January 27, 2014 I think Spacecadet is close. My understanding is that the whole LED panel flashes on and off. The amount of time On is the apparent brightness. Car LED tail lights are doing this now I notice. Medium brightness using a repeating cycle where the On time is about 50%. When the car brakes are applied they go brighter to 100% On time. The cycle frequency is usually just above human eye perception but try this: hold your head still, swing your eyes around quickly in a large circle, and mentally see if you can pick up dots or streaks. Dots will be the blinking LEDs, streaks will be 100% on LEDs or incandescent. Spacecadet might also be right if the case is a "moving" image on the display. The image shows a B, then the image panel goes Off and the B steps one LED to the left, then the image lights, and repeats. The bus and the lighted/blinking sign are speed mismatched enough that each successive sign blink is at a different bus location by enough distance to be able to see the individual blinks. Link to comment Share on other sites More sharing options...
Julesimages Posted January 27, 2014 Author Share Posted January 27, 2014 Ah yes! It must be the LED's. Other pics I have at the same time show a similar thing happening with destination text etc. whereas the tail lights are blurred. Thanks everyone for helping solve the mystery! Link to comment Share on other sites More sharing options...
spacecadet Posted January 27, 2014 Share Posted January 27, 2014 When the next generation of buses come out they'll have LED tail lights too. Link to comment Share on other sites More sharing options...
Bhandol Posted January 27, 2014 Share Posted January 27, 2014 I counted eleven B's in your pic, so the L.E.D's were blinking at 88 times per second, as your 1/8th second exposure captured the LED blinking 11 times. Parm Link to comment Share on other sites More sharing options...
Paulstw Posted January 28, 2014 Share Posted January 28, 2014 All the while the person that took the pick is all of a sudden wondering where this sale is coming from all these zooms ( I know. Stats are for registered buyers only) Link to comment Share on other sites More sharing options...
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