Motion blur test

Moving objects and moving text, for judging how much blur your display adds and why refresh rate matters more than response time for it.

Moving object

Background

Pauses first, then moves the object by a single frame so you can inspect an edge.

Speed

480 px / second

Position comes from elapsed time, so the object crosses the screen in the same number of seconds on any display.

Direction

Shortcuts

Space: Play or pause
H: Hide the controls
Esc: Leave full screen

What this test can and cannot tell you

This shows you motion blur. It does not measure it. What you see is genuine, the object moves at a known speed in pixels per second, driven by elapsed time rather than a per-frame step, but how much blur you perceive depends on your eyes, your tracking, your viewing distance and your display, and none of those are things a browser can read.

There is no millisecond figure here, for blur or for pixel response, because a browser cannot produce one honestly. Measured motion figures come from hardware review sites using high-speed cameras and photodiodes.

The serious work on display motion is Blur Busters'. Their TestUFO is where to go for the pursuit-camera method and the underlying research; this page is the plain-language version with the practical tests.

More on this: what a browser cannot detect and how these measurements work.

How to run this test

Switch the object to Text and press Play. Text is the most demanding moving object, because you have to resolve detail rather than just notice an edge.
Follow the text with your eyes as it crosses the screen. Try to read it. The speed at which it becomes unreadable is your practical blur limit.
Raise the speed step by step and note where reading stops being possible.
If your display has a backlight strobing mode, marketed as ULMB, ELMB, DyAc, Motion Blur Reduction or similar, turn it on and repeat. The difference is usually dramatic.
Compare against the same test on another device. Perceived blur is much easier to judge by comparison than in isolation.

What a problem looks like

Text that blurs but leaves no trail: Persistence blur, and it is the normal behaviour of any sample-and-hold display. Each frame is held on screen for the whole refresh interval while your eye keeps moving, so the image smears across your retina. It is not a fault and it is not pixel response.
A distinct darker trail behind the object: That is ghosting rather than persistence blur, and it comes from pixels changing too slowly. Different cause, different fix. The ghosting test is built for tuning it.
Blur that barely improves at higher refresh rates: Check that you are actually rendering at the higher rate on the refresh rate test. Persistence blur scales with how long each frame is displayed, so a genuine move from 60 Hz to 144 Hz should be clearly visible here.
Double images or a stroboscopic stepping effect: Seen most often with backlight strobing enabled, or when the frame rate and refresh rate disagree. A strobing backlight trades blur for a faint multiple-image effect, and some people find that trade worse than the blur.

What to do next

If something looks wrong, check it again in a normally lit room and from straight on, then check whether it appears on a second device. If it only happens on this screen and you are still inside the return window, that is the time to contact the retailer.

Questions people actually ask

Why is my screen blurry in motion even though response time is fast?

Because most display blur is persistence, not pixel response. On a sample-and-hold display each frame stays lit for the entire refresh interval while your eyes track the moving object, which smears the image across your retina. A panel with a one millisecond response time at 60 Hz still shows substantial motion blur.

What actually reduces motion blur?

Two things. Shorter frame times, which means a genuinely higher refresh rate with the frame rate to match. And shorter illumination per frame, which is what backlight strobing does by switching the backlight off between refreshes. Strobing costs brightness and can introduce flicker.

Is motion blur the same as ghosting?

No. Ghosting is a trail left by pixels that have not finished changing, and it responds to overdrive settings. Motion blur is a property of how long each frame is held on screen, and overdrive does nothing for it. They often appear together, which is why people confuse them.

Can you measure my display motion blur?

No. Quantifying it means photographing the panel with a camera panning at the same speed as the object, then measuring the smear in the resulting image. That is the pursuit camera method, and it needs hardware. This page lets you see the effect and compare displays by eye.