A stopwatch is a timepiece designed to measure the amount of time that elapses between its activation and deactivation.
56-411: A large digital version of a stopwatch designed for viewing at a distance, as in a sports stadium, is called a stop clock . In manual timing, the clock is started and stopped by a person pressing a button. In fully automatic time , both starting and stopping are triggered automatically, by sensors. The timing functions are traditionally controlled by two buttons on the case. Pressing the top button starts
112-486: A connector for external sensors, allowing the stopwatch to be triggered by external events, thus measuring elapsed time far more accurately than is possible by pressing the buttons with one's finger. The first digital timer used in organized sports was the Digitimer, developed by Cox Electronic Systems, Inc. of Salt Lake City Utah (1962). It utilized a Nixie-tube readout and provided a resolution of 1/1000 second. Its first use
168-538: A fast rate, while leaving no blank space between the cells. In athletics, races have to be timed accurately to hundredths (or even thousandths) of a second. A battery of electronic devices are installed in high-profile events (such as the Olympic Games ) to ensure that accurate timings are given swiftly both to the spectators and to the officials. The photo finish has been used in the Olympics since as early as 1912 , when
224-423: A film based photo finish, there is no delay from developing the film, and the photo finish is available immediately. They may be triggered by a laser , photovoltaic means, or even motion sensing done within the photo finish camera. Another method for creating this strip involves combining individual photographs. A high-speed camera or a movie camera is used to take a continuous series of partial frame photos at
280-442: A photo finish during a triathlon event in which Nicola Spirig of Switzerland and Lisa Nordén of Sweden finished the race at nearly the same time, but with Spirig ranked first. The Swedish Olympic Committee appealed the ranking. They claimed that the athletes should be ranked as joint winners because it was not clear that Spirig was ahead of Nordén. The camera on the far side of the track could have given additional evidence, but it
336-477: A stopwatch is used, there are indicators that the timing event is about to happen, and the manual action of starting/stopping the timer can be much more accurate. The average measurement error using manual timing was evaluated to be around 0.04 s when compared to electronic timing, in this case for a running sprint. To get more accurate results, most researchers use the propagation of uncertainty equation in order to reduce any error in experiments. For example: If
392-470: A strip of film is advanced past at a constant rate to produce a similar panoramic image to the digital system. A flashing LED embedded the time calibration to the film. Recently, there have been significant advances in full-frame video timing which utilizes a full sensor array rather than a single line. This has followed from the advent of low-cost machine vision technologies which has made possible systems that surpass 1/100 second time resolution. Previously,
448-418: A tower. It captures only the sequence of events on that line in the vertical dimension. Every part of each racer's body is shown as it appeared the moment it crossed the line; anything stationary is represented as a horizontal streak. The horizontal position represents time, and time markings along the bottom of the photo can be used to find the exact crossing time of any racer. The high angle allows judges to see
504-493: Is a large group of athletes (such as a combine) or if coaches are wanting to quickly time their athletes. This type of FAT technology is used widely in the world of sports performance and movement research and can be much more affordable and easy to use when compared to the camera based systems. Break-beam timing systems have manufacturers worldwide including: Dashr (USA), Brower (USA), Zybek (USA), Fusion Sport (Australia), BeamTrainer (Slovenia), and Microgate (Italy). According to
560-473: Is electronically triggered, such as a horn, is typically also wired to the timing system. In sports that involve a finish line that is crossed (rather than a touch finish, as in swimming), the current finishing system is a photo finish which is then analysed by judges. The current photo-finish system used in Olympic competition, as well as other top-level events uses a digital line-scan camera aimed straight along
616-438: The 100 m sprint, all eight athletes can be separated by less than half a second. It is not uncommon for two athletes to have exactly the same time recorded without there being a dead heat. The 2008 Summer Olympics saw the introduction of some of the fastest timekeeping equipment yet, with cameras that take photographs 3,000 times a second (compared to 1996 , which were 1,000 times per second). The 2012 Summer Olympics had
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#1732872575927672-473: The IAAF , any record in athletics ( world , Olympic, or national) or qualifying time for Olympic Games or World Championships set in a sprint event must be timed by a FAT system to be valid. Hand times, i.e. those with humans operating the stopping and/or starting mechanisms, are highly prone to error. By rule, they are only accurate to a tenth (.1) of a second, so all 100ths of a second beyond zero must be rounded to
728-788: The PowerShares QQQ 300 race in the NASCAR Xfinity Series . It is the closest finish in NASCAR history. A photo finish has occurred in the NASCAR Craftsman Truck Series four times: As of 2024, one race has had a margin of victory of 0.001 seconds in the Cup Series , which was when Kyle Larson bested Chris Buescher in the 2024 AdventHealth 400 at Kansas Speedway . Examples of similar close finishes are as follows: In horse racing , photo finishes determine accurately when
784-541: The Stockholm Olympics used a camera system in the men's 1500 metres race. The 1948 Olympics saw the finish of the men's 100 metre race determined with the use of photo finish equipment provided by Swiss watchmaker Omega and the British Race Finish Recording Company. At the finish line, photocells and digital cameras are used to establish the placings. Sometimes, in a race as fast as
840-534: The 1930s especially for the purpose of photographing moving objects. The first racing club to make use of Del Riccio's 'Photo-Chart' camera for photo finishes was the Del Mar Turf Club in California at its inaugural meeting in 1937. Unlike conventional cameras the circular flow camera used a single vertical slit instead of a shutter ; a strip of film moved horizontally across the fine vertical opening located in
896-427: The 1940s and 1950s as a means of regulating the racing industry and to reduce cheating. Betting on races became increasingly popular during the middle decades of the twentieth century. Authorities were therefore concerned to improve the probity of racing which was widely regarded as corrupt. Typically photo-finish cameras use strip photography , in which a camera is aimed at the finish line from an elevated position in
952-399: The 1968 Olympics FAT times; Jim Hines' winning time for the 100 meters was measured as 9.89 seconds, which was subsequently adjusted to 9.95 seconds. In 1972, having provided the official timing equipment since 1932, Omega lost the right to be the official timer for the Olympics to Longines. Omega returned for the 1976 Olympics. This was the first Olympics where official results were given to
1008-465: The FAT and manual times for the men's 100 meters was 0.24 seconds, although this ranged from 0.05 seconds to 0.45 seconds; for example, the average difference for the six runners in the men's 100 meter final was 0.41 seconds; while the average difference in the women's 100 meters was also 0.24, but only 0.22 in the final. In the men's 200 meters, the average difference was 0.21 seconds, and in the men's 400 meters
1064-484: The FAT time will be considered more accurate, and thus the athlete will be given the higher seed, or comparison ranking. This method of converting times dates back to when FAT systems were much less common. Hand times are increasingly less acceptable, even at low level meets, and are no longer acceptable at the upper level of the sport. Fully automatic timing did not become mandatory for world records until 1 January 1977. The first known time with an auto timing device in
1120-469: The NTSC television standard limited most VHS and SVHS, and digital frame rates to 59.94 frames per second (limiting the timing resolution to .016 seconds). Many modern systems, such as those manufactured by FlashTiming, are capable of frame rates of 120 frames per second at higher spatial resolution and in a purely digital regime. The addition of computer based analysis tools has greatly simplified and made efficient
1176-710: The Olympic Games was in the steeplechase in 1928, won by Toivo Loukola in 9:21.60 (9:21 4/5 official hand time). The device used was the Löbner camera-timer. In 1932 three systems were used: official hand timing, hand started photo-finish times, and the Gustavus Town Kirby timing device, which was designed by Kirby to determine the correct order of finish in horse races. The official report for 1932 Olympics states: "In addition to hand timing, two auxiliary electrical timing devices were used. Both were started by an attachment to
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#17328725759271232-465: The United States since the 1920s for recording race-meets but were unsuitable for photo-finish photography as the frame rate was too infrequent to catch the critical instant when horses or dogs reached the finish line. This was achieved by using a special slit camera . Lorenzo Del Riccio , a Paramount Pictures motion picture engineer improved the circular flow camera, a device which had been invented in
1288-412: The average difference was 0.16 seconds. In 1956 the average difference between the FAT and manual times for the men's 100 meters was 0.19 seconds, ranging from -0.05 to 0.34 seconds. In the men's 200 meters, the average difference was 0.16 seconds, and in the men's 400 meters the average difference was 0.11 seconds. In 1960 the average difference between the FAT and manual times for the men's 100 meters
1344-415: The clock is automatically activated by the starting device, and the finish time is either automatically recorded, or timed by analysis of a photo finish . The system is commonly used in track and field as well as athletic performance testing, horse racing , dog racing , bicycle racing , rowing and auto racing . In these fields a photo finish is used. It is also used in competitive swimming , for which
1400-419: The finish line. TimeTronics, FinishLynx, and Omega are examples of commercial timing systems commonly used in athletic competitions. These cameras have an image field only a few pixels wide, with a single frame forming a narrow image only of the finish line, and anything which is crossing it. During a race, the camera takes images at an extremely high frame rate (the exact rate depends on the system, but can be in
1456-726: The finish means that margins have been calculated to 1/100 second accuracy. In 1952 the Omega Time Recorder was the first to use a quartz clock and print out results, earning the company a prestigious Cross of Merit from the Olympic Committee. Clocks were added to slit cameras for automatic time-stamping, accurate to the 100th of a second. Despite these improvements, the overall system was similar to that used in London in 1948 (the Racend Omega Timer). The average difference between
1512-408: The focal plane. This limited the field of vision to no more than a few inches, the restricted field being aligned with the vertical line on the winning post on which the lens was focused. The strip film moved across the slit in the opposite direction to the race and at substantially the same speed as the rate of movement of the image of the horses as each passed the finishing line. This kept the image of
1568-455: The horse rankings and can factor in dead heats. The most notable dead heat was in the 1989 Hambletonian Stakes , with both Park Avenue Joe and Probe finishing in a dead heat. A photo finish decided the winner of the 2005 running of the Japan Cup , which was given to Alkaseed, narrowly defeating Heart's Cry . In 2011 with new digital technology recording vision at 10,000 frames per second, Dunaden
1624-450: The horses hit the finish line. This developed in the late 1930s, by the end of which strip cameras were used for photo finishes; prior to this point high-speed motion picture cameras were used, but did not provide sufficient temporal resolution. Stewards at the racetrack usually put up PHOTO status on the races during these photo finishes; the status of objection or inquiry can also trigger if other horses or jockeys somehow interfered in
1680-423: The horses more or less stationary with respect to the film. As soon as the first horse started to pass over the line, the camera began to record its image on the moving film from the nose backwards, progressively along the length of the body, with the arrival of every horse at the finishing post in succession. This produced a strip photographic record of the horses as they passed the vertical plane (winning post). Film
1736-402: The horses, and a set of stripes left by the neon 100th/sec intervals for accurate timing. Any perfect vertical alignment of the horses' reflection with the foreground image proved the camera was not viewing the finish line at an angle, thus incorrectly recorded the horses' relative positions. Pearl's partner was his friend, society portraitist Athol Shmith . Shmith helped accelerate processing of
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1792-537: The images taken from Tissot’s photo finish camera. Therefore the riders Taylor Phinney and Guillaume Boivin were both awarded a bronze medal. In the 2017 Tour de France a difference of 0.0003 seconds was judged by photo finish to separate the winner Marcel Kittel from Edvald Boasson Hagen , second, in the seventh stage of the race on July 7. A photo finish is possible in NASCAR . On February 17, 2018 , Tyler Reddick beat Elliott Sadler by 0.0004 seconds to win
1848-589: The line first, a photo or video taken at the finish line may be used for a more accurate check. Photo finishes make it less likely that officials will declare a race a dead heat . Finish line photos are still used in nearly every modern racing sport. Although some sports use electronic equipment to track the racers during a race, a photo is considered the most important evidence in selecting the winner. They are especially important during close races, but they are also used to assign official times to each competitor during any race. Photo-finish cameras were developed during
1904-423: The movement of their limbs and heads as they cross the line; limbs are elongated where they remain static or move backwards in relation to the slit-shutter, or truncated if they move faster than the film moving past the slit. Single-exposure photo-finish images were made by a camera that was positioned at the finish line and initially applied to horse racing. The camera’s shutter which captured 136 images each second
1960-418: The nearest 1/100 seconds. Later iterations of photo finish system began using film to record and display times, including AccuTrack that used slit technology to record images over time at the finish line to Polaroid Instant Film . Accutrack was the most popular photo-finish camera in the United States in the late 1980s and into the early 1990s, but there were some limitations to the film based cameras (the film
2016-489: The next highest tenth. Many track and field statisticians use a conversion factor estimate of 0.24 seconds added to any hand-timed mark in the 100 m or 200 m event, and 0.14 seconds to any hand-timed mark in the 400 m or longer event: these conversion factors are only applicable for comparing marks from a variety of sources, and are not acceptable for record purposes. In the case of comparing an adjusted manual time to FAT timing with an original FAT time being equivalent,
2072-407: The position of every racer in relation to the others. In a conventional photograph, the image shows a variety of locations at a fixed moment in time; strip photography swaps the time and space dimensions, showing a variety of times at a fixed location. The final image often shows a solid white background, which is a continuous scan of the painted finish line. Racers may appear distorted based on
2128-449: The process of timing races, as well as automated some portions of timing labor such with features such as motion detection and bookmarking of finish times. Owing to these developments and the lower cost compared with line-scan systems, video timing has seen some limited level of adoption at a few high-school and collegiate events. The inability of these systems to perform what is known as a "zero control test" means that they do not comply with
2184-581: The requirements of the IAAF or other national governing bodies to be classified as fully automatic timing (FAT). There are also similar timing systems that use the process of breaking a beam of light. Such systems are frequently used when athletes are tested individually. The nature of this technology does not recognize who is breaking the beam, but instead when the beam was broken (allowing it to be used in many applications outside of athletics). These systems provide instant results which can be very beneficial when there
2240-461: The result from measuring the width of a window is 1.50 ± 0.05 m, 1.50 will be σ a {\displaystyle \sigma _{a}} and 0.05 will be σ b {\displaystyle \sigma _{b}} . In most science experiments, researchers will normally use SI or the International System of Units on any of their experiments. For stopwatches,
2296-405: The sound of the starting gun firing, rather than by a direct connection, which means that the times were around 0.02 seconds faster than reality. The 1948 Olympics, however, continued to use Omega timing with a device called the 'Magic Eye', developed by British Race Finish Recording Co. Ltd. The automatic times produced in the 1948 Olympics have never been released, but examination of the photos at
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2352-482: The split button a second time allows the watch to resume display of total time. Mechanical stopwatches are powered by a mainspring , which must be wound up by turning the knurled knob at the top of the stopwatch. Digital electronic stopwatches are available which, due to their crystal oscillator timing element, are much more accurate than mechanical timepieces. Because they contain a microchip , they often include date and time-of-day functions as well. Some may have
2408-431: The starters gun. One was stopped by hand at the time the runners hit the tape. The other was provided with a motion picture camera which photographed the runner at the tape and the dial of the time indicator simultaneously." Kirby's system was also used at the 1932 US. Olympic Trials , where Ralph Metcalfe 's winning time of 10.62 in the 100 meters is considered possibly the first automatically timed world record. FAT
2464-516: The strip of negative down to 55 seconds, then to 35 seconds. These times rivaled the instant one-minute processing by Edwin Land 's newly available Model 95 Polaroid camera. Digital cameras use a 1-dimensional array sensor to take 1-pixel-wide sequential images of the finish line. Since only a single line of the CCD is read out at a time, the frame rates can be very high (up to 20,000 frames per second ). Unlike
2520-416: The swimmers themselves record a finish time by touching a touchpad at the end of a race. In order to verify the equipment, or in case of failure, a backup system (typically manual) is usually used in addition to FAT. In races started by a starting pistol , a sensor is typically attached to the gun which sends an electronic signal to the timing system when fired. An alternative starting light or sound which
2576-411: The thousands of lines per second). Computer software then arranges these frames horizontally to form a panoramic image which effectively displays a graph of the finish line (and anything crossing it) as time passes, with time denoted on the horizontal axis. Before the advent of digital photography (and still available as an alternative), a similar film -based system was used, consisting of a slit which
2632-440: The timer running, and pressing the button a second time stops it, leaving the elapsed time displayed. A press of the second button then resets the stopwatch to zero. The second button is also used to record split times or lap times . When the split time button is pressed while the watch is running it allows the elapsed time to that point to be read, but the watch mechanism continues running to record total elapsed time. Pressing
2688-431: The units of time that are generally used when observing a stopwatch are minutes, seconds, and 'one-hundredth of a second'. Many mechanical stopwatches are of the 'decimal minute' type. These split one minute into 100 units of 0.6s each. This makes addition and subtraction of times easier than using regular seconds. Fully automatic time Fully automatic time (abbreviated FAT ) is a form of race timing in which
2744-430: Was 0.15 seconds, ranging from -0.05 to 0.26 seconds. In the men's 200 meters, the average difference was 0.13 seconds, and in the men's 400 meters the average difference was 0.14 seconds. In 1964, although manual timing was also used at the Olympics, the official times were measured with a FAT system but were given the appearance of hand times. For example, Bob Hayes won the 100 meters in a FAT time of 10.06 seconds, which
2800-406: Was advanced continuously at a pace equivalent to the average speed of a racing horse, resulting in distortions of length (slower-moving horses appear to be stretched), but still preserving the order of finishers. Australian Bertram Pearl made an improvement in 1948 incorporating a mirror and neon -pulse time signature in the winning-post. This provided a precisely aligned image showing both sides of
2856-415: Was advanced on a carriage that would sometimes jam, the width of film limited the amount of data—and thus times that could be captured, etc.) and this led to occasional failures during use. Photo finish A photo finish occurs in a sporting race when multiple competitors cross the finishing line at nearly the same time. As the naked eye may not be able to determine which of the competitors crossed
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#17328725759272912-511: Was also used in 1936, but very few times have been found. In 1948, Bulova began developing the Phototimer, a unique combination of photo-finish camera and precision electronic timing instrument. The Phototimer was the first automatic timing device to be used in competitive sports. It was used extensively in North America, including at the 1948 US Olympic trials. The Bulova device was activated by
2968-452: Was converted to an official time of 10.0 seconds: the FAT systems in 1964 and 1968 had a built-in 0.05 second delay, meaning Hayes' FAT time was measured as 10.01 seconds, which was rounded to 10.0 seconds for official purposes (despite the fact that officials with stopwatches had timed Hayes at 9.9 seconds). The currently understood time of 10.06 has been determined by adding the 0.05 seconds delay back in. The same adjustment has been made to
3024-838: Was in ski racing but was later used by the World University Games in Moscow, Russia, the U.S. NCAA, and in the Olympic trials. The device is used when time periods must be measured precisely and with a minimum of complications. Laboratory experiments and sporting events like sprints are good examples. The stopwatch function is also present as an additional function of many electronic devices such as wristwatches, cell phones, portable music players, and computers. Humans are prone to make mistakes every time they use one. Normally, humans will take about 180–200 milliseconds to detect and respond to visual stimulus. However, in most situations where
3080-578: Was malfunctioning. The appeal was rejected and Spirig was declared the winner. This is the first time an Olympic triathlon result was decided on a photo finish. After a close sprint final in the Men's under-23 road race at the 2010 UCI Road World Championships in Melbourne , the organisers had to declare a dead heat between the two riders finishing just behind race winner Michael Matthews and runner-up John Degenkolb , as they were unable to detect any differences on
3136-482: Was triggered as a horse broke a thin thread on the race track. All too often, the single-exposure photo-finish camera failed to capture the decisive, first-place finish-line moment. These cameras only were used for first-place finishes, and provided no help in determining any of the other race placings. The oldest single-exposure race-track photo-finish images discovered so far were made by John Charles Hemment in 1890. Historically, motion picture cameras had been used in
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