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02-20-2013, 02:03 PM | #31 |
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Re: Question for Jeff Foster and Dave Kommel
[QUOTE=Michael Beard;370036]If you step through frame by frame on the Mason incident video
you can clearly see the camera flashes, and they do not coincide with the red light coming on. The red light comes on *after* the camera flashes, and the the pre-stage and stage bulbs go out AFTER the red light comes on.
If you're going frame by frame wouldn't the red light have to come on after the camera flash? I wouldn't expect it to come on during the flash. |
02-20-2013, 03:29 PM | #32 |
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Re: Question for Jeff Foster and Dave Kommel
Good point. The camera is stationary, on the ground, so any movement of DeFranks car should be obvious.
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02-20-2013, 04:02 PM | #33 | ||
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Re: Question for Jeff Foster and Dave Kommel
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None of it explains why the red light comes on BEFORE the pre-stage and stage lights go out in each instance. A poster on DRR mentioned they had this problem frequently at their home track: Quote:
The most bizarre thing I've ever seen is having R/T's, all incremental times and mph matching other timeslips and making sense, but having the finish ET being off by about two tenths of a second, and the MOV likewise showing about two tenths despite the cars being separated by thousandths. It happened multiple times at the same event, with different cars. How or why it happened, I have no idea, but the only plausible explanation I could come up with was that somehow the finish line sensor "missed" the front wheel, and was triggered by the back tires. A car length was roughly the amount of ET that was "missing".
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02-20-2013, 04:13 PM | #34 |
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Re: Question for Jeff Foster and Dave Kommel
Like I said, I don't know much about external flashes. Cameras also use infrared for autofocusing. The DeFrank red light could be a case of the camera autofocusing before taking the photo. I don't know if it would take that long to fire an external flash.
As for the Mason red light, there are also three other photographers on that side of the rail. Maybe one of their cameras caused it by autofocusing. It looks the photographer has to be in the right spot and take the picture at the right time for this to happen. It sure looks like there is some infrared coming from somewhere that is causing this. There definitely needs to be some testing to see what is going on so it doesn't happen again. They need to to get all the photographers together at some point during an event and have them take pictures at different angles to see if they can consistently cause this. Maybe there needs to be a car in the beams for it to happen. If they can't get it to happen then it must be the timing equipment. As for the Brand red light, the footage doesn't show if there is a photographer on the rail or not. It could be caused by autofocusing as well. |
02-20-2013, 04:23 PM | #35 |
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Re: Question for Jeff Foster and Dave Kommel
Modern DSLR's do not use infared for focusing.
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02-20-2013, 05:25 PM | #36 |
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Re: Question for Jeff Foster and Dave Kommel
Do all photographers at the track use modern DSLRs? And what about external flashes? How long of a delay is there after pressing the shutter and the flashes going off? Is this delay adjustable? It's possible to have the internal flash off and still be sending a signal to the external flashes, right? |
02-20-2013, 06:18 PM | #37 |
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Re: Question for Jeff Foster and Dave Kommel
Does anyone know if this has happened in the super gas/comp classes?
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02-20-2013, 06:58 PM | #38 | |
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Re: Question for Jeff Foster and Dave Kommel
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When you talk about external flash, I assume you actually mean remote flash. The on-camera flash units we use do have infrared, but it only functions to help the camera focus in very low light situations. Auto-focus is based on contrast and when there is not enough light for the camera to discern contrast, it uses the flash to help it focus. In the Dan Mason situation (daylight), there should not be any infrared at all, so if the photographer (possibly me) caused the redlight, it had to be flash and not infrared. Also, if the flash is turned off, there is no infrared in any situation. Remote flashes are triggered by a cable, a radio slave unit or they can be triggered by the flash of the on-camera flash. No infrared is involved. Shutter lag in modern DSLR's is very short, somewhere in the 200ms range and is not adjustable. The flash should fire instantaneously when the shutter opens.
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02-21-2013, 02:22 AM | #39 | |
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Re: Question for Jeff Foster and Dave Kommel
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I think we are putting a bit too much trust in the timing equipment itself. At brackets at the Texas Motorplex, there was a flaw in juniors. Every once in a while the dial ins would be correct but the difference in dial ins would be cut in half in the race. (I.e a 7.90-8.70 race, the 7.90 car's tree would drop just .4 seconds after 8.70 car's tree) this happened multiple times throughout the year. Just a weird nuance. What happened to the "big news" that compulink was supposed to announce after the winters. I guess that's on hold for now. Also, weren't they testing a new beam for the starting line last year at Denver? Austin Williams 464Q S/C STK Last edited by Adub464Q; 02-21-2013 at 02:23 AM. Reason: Add sentence |
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02-21-2013, 03:00 AM | #40 |
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Re: Question for Jeff Foster and Dave Kommel
There are remote flashes that are triggered by infrared.
Here's a quote I found on the web: "Because the Nikon/Canon flashes are communicating with infrared light, (as opposed to radio signals) you will need to have your remote flashes in line-of-sight of the controller flash." It's looking more and more like it's a glitch in the timing system, but as long as they have the photographers to blame, there's no need to fix it. I think you photographers need to get together with Jeff, or whoever's in charge of the timing system, and do some testing and see if you can make it happen. If it is the flash, you should just be able to fire the flash right up next to the hole in the box and it should trigger the sensor. If you guys are able to do some testing I hope you will share the results here. Last edited by Toby Lang; 02-21-2013 at 03:05 AM. |
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