Response time question

banja · 27 Aug 2008 at 03:17

If current LCDs run at 60hz, why is a response time of less than 16ms even important? Surely you won't even see any frames rendered between the updates at 1/60th (16ms) per second??

Kyo Daikun · 27 Aug 2008 at 06:22

I dont think it does, most people are only bothered when monitors have over 30 ms lag like the dell 2408

Sallermas · 27 Aug 2008 at 08:49

Response time and Input lag are different issues

Baddass · 27 Aug 2008 at 09:05

ah this old gem

response time and refresh rate are different things, dont get them confused

have a read here which should help http://www.tftcentral.co.uk/specs.htm

decto · 27 Aug 2008 at 09:30

Your eyes continue to send an image to the brain for 10ms after the image has gone.
If the response time is too slow then you'll see both the old image and the new image for the frame for most of the frame length.

Frame length + image persistance would be 26ms from 32ms (two frames) so your eyes would register two images 81% of the time ....

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banja · 27 Aug 2008 at 13:49

Baddass said:
ah this old gem response time and refresh rate are different things, dont get them confused have a read here which should help http://www.tftcentral.co.uk/specs.htm

Cheers for that. Good guide. I did realise that they were different - was just interested in how the relate to each other.

From what I can gather, the 60hz is how many images (maximum) are displayed per second, and the response is how quickly each specific image is drawn. So theoretically at least, as long as your response time is less than 16ms, you will still get your image drawn and undrawn(?) within the time it takes to move to the next image. A faster response time will just create less ghosting / give a crisper image.

MooMoo444 · 27 Aug 2008 at 14:47

decto said:
Frame length + image persistance would be 26ms from 32ms (two frames) so your eyes would register two images 81% of the time ....

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Thats giving me a headache just thinking about it..

Baddass · 27 Aug 2008 at 15:50

yeah you could look at it in that way.

ecat · 27 Aug 2008 at 15:58

decto said:
Your eyes continue to send an image to the brain for 10ms after the image has gone.
If the response time is too slow then you'll see both the old image and the new image for the frame for most of the frame length.

Frame length + image persistance would be 26ms from 32ms (two frames) so your eyes would register two images 81% of the time ....

It appears with todays LCD's and the way they work that you always 'see' the old and new image. This is the reason behind black frame interleave research etc.

Here's my favourite article on LCD tech, page 3 for retinal retention / persistence of vision. A very informative article if anyone cares to spare the time...

http://www.xbitlabs.com/articles/monitors/display/lcd-parameters.html