How does lightboost work?

[alex47]

So I set the refrest rate to 120hz. That means 120 images (frames) per second right?
But then I turn on lightboost/ULMB whatever, still on 120hz.
That means every second frame is a black one, right?
So is this then 60 actual images and 60 black frames per second or 120 actual images and 120 black frames per second?
Does that mean strobing reduces the number of actual images by half?

[Falkentyne]

No.
Strobing simply blacks out PART of an image DURING a frame. It blacks out an image for a longer time than the image appears, that way the image only appears momentarily. This causes "blurriness" (streaking) to be removed because the image is only flashed a short time.

Let's take 100hz refresh rate
the 'time delay' (persistence) of a refresh rate--how long the refresh lasts--is equal to "1000 divided by refresh rate", with the answer in milliseconds.

So 1000 divided by 100 is 10 milliseconds (10 ms).
You can also say that the "display/video input lag" of 100 hz refresh rate is 10ms, since that's how long a single frame takes.

Now, strobing blanks the screen for a large part of the 10ms, and shows the screen for a small part. The total time that the BLANKING AND SHOWING HAPPENS is equal to the refresh rate persistence of 10ms. Might make more sense if you put it into a math equation:

Refresh rate persistence= P (10 milliseconds)
Blanking period= B
Showing period=S.

So, P is always equal to B+S. P=B+S.

Now, how bright (the lightboost% value in the monitor or the slider) the screen is, and also how much blur reduction you have, depends on how long the screen is blanked out for. By logic, if the screen is blanked out longer, the screen is visible for a shorter time, since B+S must add up to P.

So, if the screen is visible for 2.5 milliseconds, the screen must be blanked for 7.5 milliseconds. The lightboost persistence value is how long the screen is visible (in this case, 2.5 ms). The lower the lightboost persistence, the darker the screen will be, but the less blurry (more blur reduction) you will have.

Except at lightboost 0%, the monitor's backlight voltage is increased to compensate for the strobing (strobing itself makes things darker due to the blanking period added)
Note: setting lightboost to 0% is the same as setting it to 100%, but the monitor backlight voltage is not increased at all, so 0% is a worthless value. Lightboost 10% is the lowest value you can use properly. This is equal to 2.1ms at 100hz, and 1.4ms at 120hz. Lightboost 100% ranges from 3ms (100hz) to 2.25ms (120hz).

[spacediver]

This user has a habit of asking questions, and not demonstrating any acknowledgement of an answer. Don't waste your time and energy on this one.