Am I interpreting this framerate test correctly? If black rectangles are moving across the screen, should I ever see any "overlaps"?

CyJackX

n00b
Joined
Apr 8, 2015
Messages
45
Hello all, I have a JU6500 40" Samsung from several years ago, and while it was so cutting edge at the time and cost me over 800$, I've always been a little wary of the actual quality of the panel. I got it more for the screen real estate than the quality, but now that I'm eyeing a better panel I'm looking into things.

For one, I've always wondered at its capacity to actually handle 60FPS as I think I got some tearing before, but after finally getting a 3070, I'm wondering about this test:

https://www.testufo.com/stutter#demo=smooth&foreground=ffffff&background=000000&pps=1920

Should I be witnessing a "gradient" of grey bars at the edges of the rectangles? It's almost as if it's simulating motion-blur. But I'd assume just with properly moving fast black rectangles, there would only be black and white. Yet I am seeing grey vertical bars on the edges. Does this mean it's not "true" 60fps my monitor is displaying? Or is it my eyes playing tricks on me due to PWM or something bizarre like that? My backlight settings are very low.

edit: attached a picture from my DSLR at 1/400sec shutter speed.
 

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Chief Blur Buster

Owner of BlurBusters
Joined
Aug 18, 2017
Messages
94
Hello all, I have a JU6500 40" Samsung from several years ago, and while it was so cutting edge at the time and cost me over 800$, I've always been a little wary of the actual quality of the panel. I got it more for the screen real estate than the quality, but now that I'm eyeing a better panel I'm looking into things.

For one, I've always wondered at its capacity to actually handle 60FPS as I think I got some tearing before, but after finally getting a 3070, I'm wondering about this test:

https://www.testufo.com/stutter#demo=smooth&foreground=ffffff&background=000000&pps=1920

Should I be witnessing a "gradient" of grey bars at the edges of the rectangles? It's almost as if it's simulating motion-blur. But I'd assume just with properly moving fast black rectangles, there would only be black and white. Yet I am seeing grey vertical bars on the edges. Does this mean it's not "true" 60fps my monitor is displaying? Or is it my eyes playing tricks on me due to PWM or something bizarre like that? My backlight settings are very low.

edit: attached a picture from my DSLR at 1/400sec shutter speed.

The better test to use is www.testufo.com/ghosting

Most TVs are VA panels which has some ghosting effects for dark colors. It's quite a common issue.

(P.S. It's also possible to do a pursuit camera with an iPhone (wave smartphone while taking a 1/30sec photo) -- for more info, you can google "pursuit camera with smartphone" for the instructions on how to interpret the Sync Track with hand-waved smartphones.)
 

CyJackX

n00b
Joined
Apr 8, 2015
Messages
45
The better test to use is www.testufo.com/ghosting

Most TVs are VA panels which has some ghosting effects for dark colors. It's quite a common issue.

(P.S. It's also possible to do a pursuit camera with an iPhone (wave smartphone while taking a 1/30sec photo) -- for more info, you can google "pursuit camera with smartphone" for the instructions on how to interpret the Sync Track with hand-waved smartphones.)
Hey Chief, thank you for the reply.
So I see the ghosts; I'm just unclear on what I should see. Does a "good" panel, OLED, or just not VA, etc, mean I shouldn't see these artifacts like ghosts, etc?
I own a video camera, I could probably do similarly using that.
 

Armenius

Fully [H]
Joined
Jan 28, 2014
Messages
23,702
The blue on the trailing edge of the boxes is normal. It will be further back depending on the panel's response time. Response time on the JU6500 is quite slow at 16.4ms. It's exacerbated by the television's 120 Hz PWM backlight dimming.
 

Chief Blur Buster

Owner of BlurBusters
Joined
Aug 18, 2017
Messages
94
Hey Chief, thank you for the reply.
So I see the ghosts; I'm just unclear on what I should see. Does a "good" panel, OLED, or just not VA, etc, mean I shouldn't see these artifacts like ghosts, etc?
I own a video camera, I could probably do similarly using that.
Correct. VA LCDs (to date) will always have some ghosting effect.

A recent LG OLED such as the 4K 120Hz CX OLED television with BFI configured to maximum while playing framerate=Hz content.

Or a modern VR headset such as Valve Index or Oculus Quest 2 VR headset -- they tune them so perfectly with zero ghosting, zero crosstalk, and zero motion blur (despite being LCD). It's the most crosstalkless strobe backlight or BFI mode I've seen lately on LCD.
 
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