.4 pro tree question

[Modernpics]

on a pro tree how long are all the lights on together like this for ?



thanks

[crikey]

In short, until either the vehicle moves or the system times out.

[Modernpics]

crikey said:

In short, until either the vehicle moves or the system times out.

best go check out ED then see if i can find a reaction time !

[Modernpics]

ok so the reaction time was 0.088

does this mean that the lights where like that for 0.088 of a second?

thanks for helping me out again andy !

[crikey]

Pre-stage and Stage lights lit = vehicle hasn't moved.
Green light lit = at least 0.4 seconds have passed.

Starter presss button, amber lights come on.
0.4 seconds later the green light comes on.
0.088 seconds later the vehicle leaves stage.

ETA, when the vehicle moves the Pre-stage then Stage lights go out of course !

Edited by crikey on Tuesday 2nd February 00:26

[dragnut]

im guessing that the green has just come on?
maybe the photo was taken a split second before the ambers go off. bulbs take a lot longer to light up and fade away (compared to LEDs).

Are they LED's in the other lane? or just a shroud around the bulb. because as far as i can see, they arent lit!

anyway, just my thoughts

[andrew37ford]

this video show's the tree well in slow motion
http://www.youtube.com/watch?v=pSKynQcfjaA

Edited by andrew37ford on Tuesday 2nd February 14:57

[ss64ii]

dragnut said:

im guessing that the green has just come on?
maybe the photo was taken a split second before the ambers go off. bulbs take a lot longer to light up and fade away (compared to LEDs).

Are they LED's in the other lane? or just a shroud around the bulb. because as far as i can see, they arent lit!

anyway, just my thoughts

But..both sets of stage and pre-stage lights are also on..

[Eurodragster Tog]

Never thought I'd be giving Dom photographic lectures but how about very fast shutter speed on the camera, ambers were still fading out - they don't go out instantaneously, they just appear to do so to our eyes.

Or, a slight variation on the above, if the picture was taken with a digital camera then even if the ambers were on for a very short time, and even if they were fading, they would still burn an image into the CCD as unlike our eyes CCDs register every photon they receive and the effect is cumulative making things look brighter than they are. That is why CCDs are so good for astronomical photography, in fact that was the first practical use they had.

The apparent instantaneous ambers and green would account for both top lights still being on since the vehicles have not yet moved. Would you rather have seen a red

[TheMighty]

ss64ii said:

dragnut said:

im guessing that the green has just come on?
maybe the photo was taken a split second before the ambers go off. bulbs take a lot longer to light up and fade away (compared to LEDs).

Are they LED's in the other lane? or just a shroud around the bulb. because as far as i can see, they arent lit!

anyway, just my thoughts

But..both sets of stage and pre-stage lights are also on..

LED's light almost instantaneously whereas it takes around 0.02 or more for a conventional lamp to achieve a significant enough brightness that we would react to it being "on". Hence some US timing systems using LED ambers have now been recalibrated so that what we call a .400 pro tree is actually .380 from the ambers to getting a green rather than a red.

Edited by TheMighty on Friday 5th February 14:31

[Modernpics]

Eurodragster Tog said:

Never thought I'd be giving Dom photographic lectures but how about very fast shutter speed on the camera, ambers were still fading out - they don't go out instantaneously, they just appear to do so to our eyes.

Or, a slight variation on the above, if the picture was taken with a digital camera then even if the ambers were on for a very short time, and even if they were fading, they would still burn an image into the CCD as unlike our eyes CCDs register every photon they receive and the effect is cumulative making things look brighter than they are. That is why CCDs are so good for astronomical photography, in fact that was the first practical use they had.

The apparent instantaneous ambers and green would account for both top lights still being on since the vehicles have not yet moved. Would you rather have seen a red

Steady on tog ;-)

What you have said is correct but its not correct for conditions like these, you have forgotten about light bleed due to the ambient light level's that being said I would still expect a fading bulb to be significantly duller than a full powered one however these are not particularly dull, if i get time I may pull luminance reading for both sets of lights and see what the difference is. bearing in mind that the car has already started to react to you can assume that the frame is at the end of the 0.88 reaction time wouldn't you expect the bulbs to be about out or totally off

[Eurodragster Tog]

0.88 yes, but you said 0.088 further up. I would not be at all surprised if light bulbs took longer than 0.088 seconds to go out.