From NASA.gov [nasa.gov]:
While thousands turned out watch NASA's Space Launch System (SLS) recently complete a full-scale test of its booster, few were aware of the other major test occurring simultaneously. NASA's High Dynamic Range Stereo X (HiDyRS-X) project, a revolutionary high-speed, high dynamic range camera, filmed the test, recording propulsion video data in never before seen detail.
The HiDyRS-X project originated from a problem that exists when trying to film rocket motor tests. Rocket motor plumes, in addition to being extremely loud, are also extremely bright, making them difficult to record without drastically cutting down the exposure settings on the camera. Doing so, however, darkens the rest of the image, obscuring other important components on the motor.
Traditionally, video cameras record using one exposure at a time, but HiDyRS-X records multiple, slow motion video exposures at once, combining them into a high dynamic range video that perfectly exposes all areas of the video image.
Gizmodo [gizmodo.com] adds:
According to a statement from NASA, scientists tried out the camera while testing its booster, QM-2. They monitored the camera from a safe distance, but its automatic timer failed to go off, meaning scientists had to start it manually.
And apparently, the force of the booster test was so great that it disconnected the camera’s power source. So NASA got confirmation that its camera works, but also that its rocket is very powerful.