This test needs a camera with a high-speed-video function (480fps+). An example recording is High Speed Video of LightBoost. This test is useful for capture display refreshing behaviour, including scanout behavior. Use full screen mode with caution.

This mode is good for photodiode oscilloscopes. It slows down the flicker to your preferred flicker rate. This is useful because LCD pixel response can overlap multiple refresh cycles. See Pixel Response FAQ: GtG versus MPRT

Test lag of different computer setups via a high speed camera filming both the screen and mouse at the same time. This test flashes upon mouse click. With a high speed camera, this can measure relative latency differences between systems and/or settings changes. There are many latency error margins including browswer, graphics drivers, displays, display scanout, refresh interval granularity, camera frame rate granularity, and full screen versus windowed lag. For this reason, compare only via many test passes only on the same system, while changing one variable (i.e. different browser or different mouse, to compare lag differences). Inspired by this tweet.