RealNC wrote:Chief Blur Buster wrote:The link is broken -- that image is now deleted.
It was weird. Some of the boxes were partially lit. Normally, a box if either unlit or lit. In this case, part of a box was unlit, and some part of it was lit.
For
http://www.testufo.com/frameskipping
That's probably a slow camera sensor scanout temporally interacting with display scanout.
If your camera creates jelly effect during fast pans, that's a slow camera sensor, and can generate this strange artifact. Especially with PWM backlights and strobe backlights. But has happened on high-Hz sample-and-hold displays with slow camera sensors too. However, most modern cameras now have sensor scans faster than the refresh cycle of a high-Hz monitor.
One can compensate for that effect by stepping back further away from the display before taking a photo. A half-height scan is done in half the time, so you can eliminate this artifact simply by stepping away from the monitor and making sure that the photographed grid covers less vertical height of a landscape photograph (the camera sensor scan direction is top-to-bottom or bottom-to-top when the camera sensor is in landscape mode).
Also, make phone camera in landscape mode, not portrait mode. This is usually not important for fast sensors, but it can help slow camera sensors -- to keep the scan direction along the same axis on both screen and the camera. Landscape photo of landscape monitor, keeps the scan more in sync.
This kind of artifact is rare but when this happens, it's easily fixed by doing 1 and/or 2 and/or 3. Doing only one of the below may be all you need, but you may need to fix multiple factors.
1. Use phone camera in landscape mode when photographing monitor
2. Use longer camera exposure.
3. Don't photograph with large squares (e.g. too close to monitor or using too few squares), instead use a denser grid or step further away from monitor