Display Motion blur is Blur Busters' speciality. So allow me to explain.
Other people above mentions source-based motion blur (e.g. blur built into movies), but does not specifically explain sample-and-hold motion blur, which is endemic to many LCD/LED televisions until recently. So, excluding source-based motion blur:
Originally Posted by primetimeguy
Been thinking about this a bit and google didn't turn up any answers for me.
My question is why don't we see motion blur in real life, at the least to the point we do on modern LCD/LED tvs?
We do see motion blur in real life, but we're so used to it, we don't "realize" it's motion blur. For example, stare straight ahead in real life, while you wave your hand back and fourth very very fast across your face. That's motion blur created by your human brain.
CRT/plasma with decaying phosphors or strobing backlight for LED/LCD reduce the effect, but real life does not have decay or strobing effect so why don't we see motion blur in real life?
That's because real life has infinite frame rate
There are no static frames in real life. Real life does not operate on a frame rate. The human brain does not operate on a frame rate.
The Scientific Explanation
My gut says what we see on LCD/LED should be more like real life since there is no decay, but blur on these sets is very noticeable to me so wondering where my thought process is wrong.
This is called the "sample-and-hold" effect, also shown in scientific references
(many science/academic links). In simple explanation:
- LCD/LED displays static frames continuously.
- Your eyes are moving while tracking moving images.
- Your eyes are in a different position at the beginning of a refresh than at the end of a refresh.
- Therefore, the static refreshes are blurred across your retinas.
- That's motion blur.
Repeat this process every refresh (e.g. 60 times a second). On a continual basis. As a result, Your eyes are always seeing 1/60sec worth of motion blur. This is the motion blur caused by sample-and-hold. This motion blur has nothing to do with the speed of pixel transitions (GtG). This motion blur even occurs on 0ms instant-pixel-response displays, if the frames are still displayed continuously and statically.Self-Explanatory Animation
See this Web Animation on TestUFO: http://www.testufo.com/eyetracking
View this in a recent web browser on an LCD display at 60fps. This demonstrates eye-tracking based motion blur -- the motion blur enforced by static frames on a sample-and-hold display.How Do You Fix This Motion Blur?
the length of individual static frames.
..........Via strobing (e.g. CRT, plasma, strobe backlight)
..........Via more frames/refreshes (e.g. extra unique frames in extra Hz, either original frames or interpolated frames)
..........Via infinite framerate (e.g. real life. No frames are static)
Otherwise, the static frames gets smeared across your eyes
.The Simple Photographer's Analogy
Eye-tracking of moving objects on a 60Hz LCD. A frame continuously displayed for 1/60sec will create the same amount of perceived motion blur as waving around a digital camera (1/60sec shutter) while trying to take a picture at the same panning speed. The sensor (eye, camera) is moving relative to the material (scenery, static frame on display). e.g. If the scene moves 1 inch during 1/60sec, you get 1 inch of motion blurring trail.
Now use a fast shutter. 1/1000sec for example. Try taking a picture while moving around the camera. You get no motion blur (or only very little). Likewise, a display that has 1/1000sec static frames (e.g. brief strobes, or "1000Hz" display), you will get far less motion blur this way.
However, a 60Hz LCD without strobe backlight, without interpolation, will have the same amount of motion blur as a waving digital camera set to a 1/60sec shutter. Moving eyes, moving camera, creates the same amount of perceived/photographed motion blur on the static material (e.g. static scenery, static frame) for the same panning speed.Edited by Mark Rejhon - 9/29/13 at 12:28pm