Best way to test display lag?

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Chief Blur Buster
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Re: Best way to test display lag?

Post by Chief Blur Buster » 13 Jan 2014, 18:35

Check this out for an alternative method of measuring input lag -- see this forum thread

EXCLUSIVE: We measure G-SYNC Input Lag in GSYNC Preview #2
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Re: Best way to test display lag?

Post by nimbulan » 13 Jan 2014, 19:21

Chief Blur Buster wrote:Check this out for an alternative method of measuring input lag -- see this forum thread

EXCLUSIVE: We measure G-SYNC Input Lag in GSYNC Preview #2
If only I had the money to buy a high speed camera to try that...

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Re: Best way to test display lag?

Post by RealNC » 14 Jan 2014, 08:02

sharknice wrote:
RealNC wrote:Maybe you can get away with just one computer, but with two identical mice. Each mouse will give you a different cursor
Unless you're using some sort of special program you only get one cursor no matter how many mice you connect.
Hm, never tested it on Windows. On Linux you get two cursors. Maybe install some Ubuntu in order to test, then.
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Re: Best way to test display lag?

Post by Chief Blur Buster » 14 Jan 2014, 16:32

nimbulan wrote:
Chief Blur Buster wrote:Check this out for an alternative method of measuring input lag -- see this forum thread

EXCLUSIVE: We measure G-SYNC Input Lag in GSYNC Preview #2
If only I had the money to buy a high speed camera to try that...
You can now get a basic 1000fps camera for only $200. The 1000fps-capable camera that I used, costs me only $250 off eBay. As you notice, the footage is low resolution (224x64) but that's all the resolution you need for high speed input lag tests like these.

Some example cameras: GoPro Hero3 (240fps), Casio EX-FC200S (1000fps), Casio EX-ZR200 (1000fps), EX-F1 (1000fps),Fuji HS10 (1000fps), Nikon1 J1 (1200fps), Nikon1 J2 (1200fps), Nikon1 V2 (1200fps).

Some of these are only $150 now, and others are a bit above $1000.
Entry-level high speed video has finally become reasonably cheap. The quality is low and postage stamp sized, but very useful for latency testing, as well as strobe backlight tests (including the good old high speed video of LightBoost).
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Re: Best way to test display lag?

Post by nimbulan » 14 Jan 2014, 16:50

Chief Blur Buster wrote:You can now get a basic 1000fps camera for only $200. The 1000fps-capable camera that I used, costs me only $250 off eBay. As you notice, the footage is low resolution (224x64) but that's all the resolution you need for high speed input lag tests like these.

Some example cameras: GoPro Hero3 (240fps), Casio EX-FC200S (1000fps), Casio EX-ZR200 (1000fps), EX-F1 (1000fps),Fuji HS10 (1000fps), Nikon1 J1 (1200fps), Nikon1 J2 (1200fps), Nikon1 V2 (1200fps).

Some of these are only $150 now, and others are a bit above $1000.
Entry-level high speed video has finally become reasonably cheap. The quality is low and postage stamp sized, but very useful for latency testing, as well as strobe backlight tests (including the good old high speed video of LightBoost).
Wow I had no idea that compact cameras with high speed recording capability were available. I was looking at a Kickstarter the other day for the "first affordable high speed video camera" from last year and it was still $5000, though it does go up to almost 18,000 fps.

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Re: Best way to test display lag?

Post by sharknice » 14 Jan 2014, 17:29

I'm thinking about getting the Casio Exilim EX-ZR200 since it is only $150 and can do 1000 fps.
Do you think that would be sufficient for doing an input lag test like what you did using an LED?

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Re: Best way to test display lag?

Post by Chief Blur Buster » 14 Jan 2014, 17:59

sharknice wrote:I'm thinking about getting the Casio Exilim EX-ZR200 since it is only $150 and can do 1000 fps.
Do you think that would be sufficient for doing an input lag test like what you did using an LED?
Yep. That's the camera I used for GSYNC Preview #2. It was $250, but the price has fallen.

Blur Busters is also now looking guest writers (possibly paid), that has the time to do more extensive latency tests. I can provide step by step modification instructions for a Logitech G9x, with a soldering iron, unless you're already familiar with how to do it. (A 3V coin battery is wired in series with the LED, and the mouse button completes the circuit).
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Re: Best way to test display lag?

Post by sharknice » 14 Jan 2014, 18:30

Chief Blur Buster wrote:
sharknice wrote:I'm thinking about getting the Casio Exilim EX-ZR200 since it is only $150 and can do 1000 fps.
Do you think that would be sufficient for doing an input lag test like what you did using an LED?
Yep. That's the camera I used for GSYNC Preview #2. It was $250, but the price has fallen.

Blur Busters is also now looking guest writers (possibly paid), that has the time to do more extensive latency tests. I can provide step by step modification instructions for a Logitech G9x, with a soldering iron, unless you're already familiar with how to do it. (A 3V coin battery is wired in series with the LED, and the mouse button completes the circuit).
It would be nice if you provided some sort of instructions for doing that. I think I have all of the equipment I need for it but it would nice to see a picture on where to connect it. I have a couple mice I could try it ion.

For a non-mod alternative you could probably test keyboard input lag by binding something to scroll lock, caps lock, or num lock and use the LED indicators.
My Corsair K95 Keyboard also has a special mode where the LED on the key lights up only when you hit it.

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Re: Best way to test display lag?

Post by nimbulan » 14 Jan 2014, 18:57

sharknice wrote:For a non-mod alternative you could probably test keyboard input lag by binding something to scroll lock, caps lock, or num lock and use the LED indicators.
My Corsair K95 Keyboard also has a special mode where the LED on the key lights up only when you hit it.
That's actually a good idea, but there may be some lag involved in the keyboard LEDs as well. If there is, it would be near impossible to measure since you won't be able to visually gauge the contact point of the keyboard key that's triggering it.

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Re: Best way to test display lag?

Post by HeLLoWorld » 15 Jan 2014, 16:14

hate to crush dreams :) but numlock and such are actually commanded by your main processor, this was already the case on a 8086! I was shocked too when I learnt that a long time ago!
So there would be some uncertainity about the time of the roundtrip, potentially not negligible.
If the keyboard has full-local circuitry to light up custom leds thats another story of course.

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