Photo finish question
 

I've often wondered where the photo finish point sits exactly on the mirror. My guess would be the very centre but I would like to know if this is the case and whether all tracks would be the same?

Doc, you’re up.

Jamee, hang on to your hat. Lots of experts here on this subject.

I still have a good hold of my hat. :headbanger:

Anyone able to shed any light?

It would make sense for the center to be the standard... but the reality is that the actual finish line is wherever the camera is truly aligned parallel to the mirror.

Looks like the experts don’t want to,play

I suggest you do a search of the board for threads on the subject. There are several.

Here is a good one:

http://www.paceadvantage.com/forum/s...sh+line+mirror

Another

http://www.paceadvantage.com/forum/s...sh+line+mirror

I'm nearly certain I was told it was aligned to the center of the mirror when I saw it in action, but it has been a while and don't want to state it as fact.

When I worked as a placing judge, we matched the finish- slit up to the mirror's center. Somehow, it always shifted, and with us reluctant-especially during winter-to trudge across the surface, it usually STAYED misaligned.

That's one reason-but not the only reason- I never trusted mirror images in determining order of finish. For me, the mirror was only a LAST resort.

I will say it was sometimes helpful before high def and colored splashdowns in discerning which runners the noses belonged to. Working with fuzzy black and white images, that part could get much more dicey than players might have realized.

Just saw this thread.

Our Finish Lynx system had a calibration program that I ran pre-race each day, that assured (based upon STABLE points perpendicular to opposite sides of the track) where the exact point of the finish line was. In British Columbia, we had a federal regulator (we called him regulator Rick) who would RANDOMLY come up to my office and have me run that program in his presence to assure it was done regularly. When you ran the program, those stable points would leave an image (when the camera was running continuously) would leave EQUALLY spaced lines on the top and bottom of the scan.....If they were NOT equal,we would have to carefully manipulate the angle of the camera until they were of equal representation on the continuous scan.

I had to trudge out to the inner rail at once or twice a season, and clean the mirror (particularly when the Woodbine surface was PolyTrack that stuck on everything including your shoes walking out there...NASTY STUFF particularly when it got hot out)

If there was ANY question about perpendicularity (which I NEVER SAW) it would have been most likely from NOT having run that calibration program. On the computer screen image we had a perpendicular line that was mobile (laterally) that would be placed over each nose...IF the mirror and scanned image were out of alignment, that line WOULD NOT touch both noses exactly the same and that was something I NEVER SAW ONCE at the thoroughbreds of standardbreds.

To the original question: CENTER of the mirror

True that would work as long as BOTH point were EXACTLY perpendicular to one another and was used as a STANDARD for all the races.

Because the mirror on the main course (Woodbine) is about 8 inches beyond the finishing POST, a lot of people misjudge the finish order and I have had to show disgruntled owners and trainers (who came up to the roof and yelled at the steward) many times, the image DIRECTLY off my computer screen what the order of finish was..We had one case of a fellow even hiring a lawyer (who, sadly did not know a thing as to how the system worked) to argue his case ....Waste of time, effort, and $$$$$

A little trick the stewards showed me was to place the laterally moving perpendicular line over the PLACE horse to show that the nose of the winner was out front.

Tech is a wonderful thing. Lol. We could have used it back when I worked the placing stand. Omg.. I HATED to walk across a wintry or wet surface. It was unavoidable, though, on days when I operated the infield tele-timer. But that's another topic for another time.

Jamee, there ya go!

I had trouble with the OLD OLD system of timing at little Fraser Downs (standardbred track) in Cloverdale British Columbia.

THIS OLD system was based upon a beam across the track (sent from the outside to a "catcher" on the inner rail) and would would go active about 3 to 4 seconds before the first horse would interrupt the beam.....I had a series of lights on the computer screen that would sequentially come on as each was ACTIVE (this delayed activation was used in case a bird, or debris might fly between the beam and the catcher "cup" across the track to activate that timing point BEFORE the horse actually got there)

Each day before the races, I would run a program to check to see if all was working, and ALMOST DAILY, I had to ask a fellow out on the track to check an alignment that was not working and they were fragile...had two examples of a very strong wind moving them, but the MAJOR source or error was snow filling the receiver cup during a program as we raced all Winter in the evening.

I would have a stopwatch as a backup...

THE BIGGEST problem I had at that little track was on the weekends when we ran during the day.....Winter time this far NORTH gives dark shadows earlier in the day. As it became later, the grandstand shadow crept UP the stretch to eventually be right on the finish line...If you know photography, the exposure on the SUNNY (inner rail) side of a scan would be about f16 but in the shadow right next to it, a mere f4..I had to use a special holder to slide down neutral Density Filters progressively as this shadow occluded more and more of the scan. Late in the day, that shadow moved faster and the camera being on a different floor that I was,means I had to run up and down all day adjusting the mid point between these two extremes.

Another problem,usually in the Spring, were clouds...When a cloud came over (and this was an old MANUALLY functioning exposure camera) the entire can would require opening the internal iris to a higher f stop....Now since the camera was DOWN STAIRS to me, if an exposure set for bright or cloudy CHANGED from the time I initially set it, it would either over or underexposed at the wire. I told the judges that ONE DAY the potential was that thing would change (exposure wise) dramatically form the time I set it,and the time the scan was made at the finish....It happened, luckily ONLY ONCE and I was able to save an image (for order of finish purposes, but NOT of good enough quality for a public image).

At Woodbine, we had a much better Finish Lynx system that had automatic exposure,so it was much easier...At night you set it once since all the conditions of ambient light were the same every race. There the problem in the Day (particularly when the sun was going down) was White balance..You would have to white balance every race until if got dark.

Enjoying all these posts! Thanks, participants.

Lots of mnr's eyes didn't work during the time I subbed in as operator. This necessitated catching the fraction manually and if the angle was bad, using (sometimes distant) landmarks for orientation.

That old smokestack across the river sure came in handy for half-mile splits at 5 1/2 furlongs. I could get serious and profer my theories on how poor angles from the drf vantage point distorts margins at certain points of call, but I haven't so much as glanced at this evening's pp's, and it's already 1:30.