What Refresh Rate Causes No Motion Blur On TV?

It’s a common perception that fast-moving scenes on a TV often appear blurry.

However, as the TV’s refresh rate increases, the motion usually looks smoother and more fluid.

That said, some believe that beyond a certain refresh rate, the improvement in motion clarity and overall picture quality becomes quite insignificant too.

A refresh rate of 120 Hz or 144 Hz almost completely eliminates the motion blur on a TV.

Let’s discuss the effect of different refresh rates on motion blur in this article.

Refresh Rate & Frame Rate

The refresh rate of a TV indicates how many times the screen updates itself every second.

In simple terms, refreshing means replacing the current frame with a new one.

The duration it takes for the TV to complete one such update can be called refresh time, which is the inverse of the refresh rate.

Frame rate, on the other hand, refers to the number of frames per second (fps) sent to the TV by the source.

This value may or may not match the TV’s refresh rate.

The time taken to deliver each frame from the source to the TV can be called frame time, which is the inverse of the frame rate.

Sample and Hold Displays

Modern TVs, whether OLED or LCD, operate on the sample-and-hold principle.

In this process, each sample or frame of a video, essentially a still image, is held on the screen for a brief moment, typically a fraction of a second, before being replaced by the next one.

The transition between frames occurs seamlessly, without the screen going black in between, giving the feel of continuous motion.

Because these frames change rapidly, our eyes perceive the still images as moving.

Some research suggests that most people perceive motion when images are displayed at around 24 to 30 frames per second (fps), though this perception can vary.

Some individuals find motion smooth only at higher frame rates, such as 50 to 60 fps.

With that understanding, let’s now understand what causes motion blur.

What Is Motion Blur?

Motion blur is a visual phenomenon perceived by the human eye, occurring when the rate at which frames change on the screen doesn’t align with the speed our eyes expect to follow.

Thus, it’s important to note that motion blur is just a visual perception, not something virtually generated by the screen itself.

60 FPS vs 30 Hz

If a TV has a refresh rate of 30 Hz, it means the screen updates itself once every 33.3 milliseconds (1000 ÷ 30).

Similarly, TVs with refresh rates of 60 Hz, 120 Hz, and 240 Hz refresh at intervals of 16.6 ms, 8.33 ms, and 4.16 ms, respectively.

Now, imagine you’re playing a game running at 60 frames per second (fps).

For the motion to appear smooth, the TV should ideally refresh at 60 Hz, so that every frame is delivered and displayed for the interval of 16.6 ms each, matching what your eyes expect.

However, if you play the same game on a 30 Hz TV, each frame remains on the screen for twice as long, i.e., 33.3 ms.

As a result, your eyes anticipate faster frame changes, but the display lags behind, making motion appear blurry or less fluid.

Or, you can understand it as the screen wants to display a frame till 33.3 ms, but in the midway duration, the source sends a new frame which may cause screen tearing.

Conversely, when playing on a 60 Hz TV, the refresh rate aligns with the frame rate, resulting in smoother motion.

That said, if you try running a 120 fps high-speed game on a 30 Hz TV, the mismatch becomes even more pronounced, leading to significant motion blur, despite an improvement in the overall latency.

In essence, higher refresh rate TVs greatly reduce motion blur compared to those with lower refresh rates, offering clearer and smoother motion performance.

30 FPS vs 60 Hz

Now, consider the opposite scenario.

Suppose you’re playing a 30 fps game on a 60 Hz TV.

In this case, each frame is meant to stay on the screen for 33.3 milliseconds, while the TV refreshes every 16.6 milliseconds.

This means the TV refreshes twice during the display time of a single frame, effectively showing each frame twice.

This results in a frame-doubling effect, where the same image is refreshed twice or a few more times before the next frame arrives.

The effect is more noticeable on OLED TVs, as they have very low response times and transition almost instantly between frames.

However, on many LCD TVs, which generally have slower pixel response, this can appear as slight motion blur.

That’s because even though the frames repeat correctly, the LCD pixels may not change colors fast enough, causing the image transitions to appear smeared or less crisp.

When Is Motion Blur at Its Minimum?

If you use a 60 Hz TV and play a game that runs at a slightly higher frame rate, you’ll usually experience exceptionally smooth motion without any noticeable screen tearing.

Now, why “slightly higher” fps? Let’s understand.

A 60 Hz TV refreshes its screen every 16.6 milliseconds.

Ideally, the game’s frame rate should match this refresh rate to sync perfectly with the screen.

However, in reality, there’s often a small processing delay from the graphics card, let’s assume about 1 millisecond.

To compensate for this delay, the source must deliver frames a bit faster, within 15.6 milliseconds instead of 16.6 ms.

That translates to a frame rate of roughly 1000 ÷ 15.6 = 64.1 fps.

Hence, when the game’s frame rate slightly exceeds the TV’s refresh rate, it helps counter minor processing lags, ensuring that motion remains smooth and blur-free.

What Refresh Rate Completely Eliminates Motion Blur?

On a 30 Hz TV, each frame updates every 33.3 milliseconds.

When you move to a 60 Hz TV, the update interval is halved to 16.6 milliseconds, an improvement of 16.6 ms that greatly reduces motion blur.

Switching further to a 120 Hz display shortens the refresh time to 8.3 milliseconds, which is still a notable improvement, though only half of what you gain when moving from 30 Hz to 60 Hz.

Going beyond that, from 120 Hz to 240 Hz, the improvement halves again, with only a marginal benefit.

Upgrading further to 360 Hz offers even less practical advantage, since most video and gaming content today typically runs at 24 fps, 30 fps, 60 fps, or 120 fps.

Moreover, theoretically the smoothest motion would occur if frames refreshed every 0 ms which leads to infinite Hz display, even a refresh time of 1 ms is equivalent to 1000 Hz.

Such refresh rates far exceed the needs of current content and human visual perception.

In practical terms, a TV with a maximum native refresh rate of 120 Hz or 144 Hz should strike the perfect balance, delivering fluid, almost blur-free motion for movies and gaming without unnecessary cost.