Question for Jeff Foster and Dave Kommel

[Dave Kommel]

Modern DSLR's do not use infared for focusing.

[Toby Lang]

Originally Posted by Dave Kommel

Modern DSLR's do not use infared for focusing.

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?

[Jody Lang]

Does anyone know if this has happened in the super gas/comp classes?

[Adub464Q]

Originally Posted by Jody Lang

Does anyone know if this has happened in the super gas/comp classes?

I'm not sure about this exact situation, but at the Dallas national last year, the final two pairs of super comp in round 2 had to be rerun. This was because the tree dropped and everything was good. No incremental times/final times or rts. All zeroes and no winlight. Very strange deal.

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

[Toby Lang]

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.

[Dave Kommel]

Originally Posted by Toby Lang

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?

99% are using modern DSLR's. You might have friends and crew shooting with point and shoot cameras that use infrared focusing.

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.