Frequently asked questions

Photo Finish transforms android smartphones into a precise, fully automatic sports timing system. This allows you to accurately time runs, reaction speed and sprints for various sports. Of course, you can also make time measurements during technical parcours. With Photo Finish we want to offer athletes, coaches and physios involved in improving sports performance a powerful training tool. The app motivates athletes to keep investing in improving their performance.

You just need your Android Smartphone! If you want to connect two or more phones with Photo Finish Pro, all connected phones need an internet connection for the transmission of times. Since wifi is mostly not available at the track, you likely need mobile data. If you only have one SIM card, you can also create a mobile hotspot with one of your phones and join with the other phones. Note that this is not recommended because of the limited range of wifi. Photo Finish needs almost no data (way less than 1 Mb per training session), therefore a small volume flat rate or even prepaid is completely sufficient.

Measurements with a single smartphone can be performed for free with Photo Finish BASIC mode. If you wish to connect multiple devices, or take advantage of the ADVANCED or SERIES modes (which, for example, offer different starting types or the ability to add multiple athletes at once), you will need Photo Finish PRO! If you want to try it out, go ahead! The first 7 days are completely free. If you decide to cancel within the trial period, there are no costs at all. Importantly, only the mobile phone initiating the session needs Photo Finish PRO, so you can connect as many devices as you want with just a single Photo Finish PRO license!

Use the basic mode for a simple setup for your personal training.

In this mode, the stopwatch starts at the first trigger of a connected device. Every time a phone’s camera detects an athlete, a new intermediate time is measured. For example, measure lap times with one phone and flying sprints with two phones. Connect as many additional phones as you need to measure intermediate times.

In basic mode, you define one participating athlete.

You don’t need Photo Finish PRO to use the basic mode with one phone, so you can use this option completely for free!

Use Advanced Mode for more start types and multiple athletes.

Connect multiple phones to add as many measurement points as you need. Moreover, you can specify as many participating athletes as you want.

In Advanced Mode, you manually release the start via any connected phone.

Use the series mode for fully automatic exercises with multiple athletes.

In this mode, you define a series that automatically runs without having to touch the phones again after initial setup. Choose any number and order of athletes. Add breaks between the individual athletes, set a number of series, and a series break.

During the break, Photo Finish shows and tells you which athlete is up next.

The "Flying" start starts the stopwatch on the first trigger of a connected device.

Use "On your marks, set, go" for a typical starting sequence out of the blocks.

With the "Shot detection" start, the stopwatch starts as soon as Photo Finish detects a loud sound.

"Three, two, one, go" uses four evenly timed tones and starts the stopwatch on the last tone.

With the "Thumb" start, place your thumb on a connected phone. The stopwatch starts as soon as you let go of the phone.

Very accurate: Photo Finish is more precise than an expensive light barrier system. This is because Photo Finish uses image recognition to determine the chest position of the athlete. A light barrier can also be erroneously triggered by the hand or knee. We conducted a study were we found that over 75% of all measurements were accurate to within 0.01s and the remainder to within 0.02s. You can find our study unter the following link:

With good lighting conditions and precise phone alignment, Photo Finish gets a really high accuracy. You can convince yourself of the accuracy with a simple test: Place two smartphones connected to the same session opposite to each other on the same target line and align them exactly vertically and to the respective other camera lens. Then run across the finish line a few times. If the alignment is precise, both smartphones capture the runner at the same time. Typically the times differ by only 0.01 seconds or less.

Each Phone can only cover one runner at a time. But with some creativity you can time multiple athletes. For example you can set up 2 phones between lane 2 and 3 on a track, covering lanes 1 and 4. Then you need a third phone at the start. Now you can time duel sprints !

Absolutely! With Photo Finish PRO, you can export all your data, including every run for each athlete, into a CSV file. To perform the CSV export, simply click on the "Share" button in the history tab.

Yes you can. Keep in mind that most bluetooth speakers have a big audio delay. Photo finish uses the microphone of your smartphone to counteract this behavior and to ensure the accuracy of the timing. Please make sure that the bluetooth speaker is within 3m of the smartphone that starts the run for maximum accuracy.

Warning: Do not use headphones with Photo Finish, because loud beep may cause damage to your hearing.

Photo Finish uses Bluetooth Low Energy to connect to other nearby devices. To use this technology, the app needs access to the device location.

This increases accuracy. The reason is the varying delay caused by the operating system between the moment when Photo Finish plays the starting signal and the moment when it can actually be heard. Photo Finish uses the microphone to register the starting signal and can, therefore, determine the time at which it was actually played more precisely.

The analysis and calculation of the crossing time takes a little moment. However, this does not affect the accuracy itself, just as the manual photo finish evaluation at competitions does not affect its accuracy. The beep is only played after the images have been evaluated.

Photo Finish operates at 30 frames per second when the detection is active, a rate that ensures real-time operation on most modern smartphones, even those less powerful. An athlete crossing the finish line is thus captured 30 times per second and the chest position is calculated at the respective times. The exact moment at which the chest crosses the finish line is calculated using a cross-multiplication from the chest positions and the frame times directly before and after the crossing. This method greatly increases the time resolution. Photo Finish displays the frame directly after the finish line by default.

No. However, we recommend a tripod for the best accuracy, reliability and usability, since the precise alignment of the smartphone in particular is otherwise not possible.

You can set up the devices as far apart from each other as you like! This is possible because the transmission of the times occurs via the internet. However, it’s important to note that the phones need to be in close proximity to each other (within a 5-meter range) during the initialization of the connection, since it happens over Bluetooth.

In these modes the detection of the app is not designed to do a standing start, low start position or start when the runner is already in view of the camera. So, please note that the detection requires at least a 1.5-2m run-up to function properly.

In some cases an athlete might be missed by Photo Finish. The reliability depends partly on the quality of your phone’s camera.

A good set-up avoids misssed detections. Make sure you position your phone on a tripod somewhere between hip to chest height. The athlete passing the phone should be at a distance of 1m to less than 3m. Rule of thumb is that you should see the athlete fully on the screen. At high speeds, the minimum distance from the mobile phone should be greater. For professional adult sprinters, we recommend positioning the phone 1,4-1,6m from the closer line of the running track, so that middle of the track is roughly 2-2,2m away.

Problem: Sun or lights that shine directly into the camera lens Solution: Reposition the phone

Problem: Darkness Solution: Create Light or end your session

Problem: Low colour contrast between athlete and background Solution: Use a shirt with a different colour then the background (or a vest)

Problem: An athlete passing too close by the phone Solution: Increase the distance to a minimum of 1 meter, but we recommend 2 meters

Problem: Drops of rain over the camera lens Solution: Use a shelter for your phone

Problem: Moving backgrounds (people, cars) Solution: Reposition the phone

We have put a lot of effort into making the connection setup as stable and comfortable as possible. Nevertheless, it can occasionally happen that a connection setup does not work. In this case you can try to switch bluetooth off and on, restart Photo Finish, or restart the affected devices. A bad internet connection can also affect the connection process. In addition, when connecting more than two phones, it is recommended to join one after the other with the clients. Phones trying to simultaneously connect to a host can sometimes disturb each other.