[h3ctic]

Yes, apparently it only has a latency of 21ms

[ksd482]

21ms sounds really low, which is good of course.

But as humans, would we notice 21ms lag while writing even if we paid close attention?

[jm_l]

You would definitely notice a 21ms lag while writing. Ideally you want to get below 10ms, but for physical-object-like responsiveness 1ms is the standard. See this old video from Microsoft research which demonstrates

https://www.youtube.com/watch?v=vOvQCPLkPt4

[braythwayt]

The original Apple Pencil and first generation of iPad Pro boasted of a 20ms lag. That was considered impressive, but perceptible if you look at your writing carefully.

I found it fine for note-taking, but lots of people would still notice the latency, especially those using creative tools where there is a strong feedback loop between what you see and what you draw.

They are now claiming 9ms lag. I suspect this is imperceptible for the use case of note-taking and marking up PDF documents (e.g. highlighting, making notes in the margin).

But then again, 20ms is going to be more than fine for that use case as well.

[infogulch]

I think you have to get below 10ms for humans to be unable to notice. Drawing is a worst case scenario for exposing screen latency; it's hard to match reality's 0ms and a pen with a fine tip doesn't help hide any of it like a comparatively chunky finger does. That said, 40ms -> 21ms is a really big improvement which could make the experience go from awkward to quite usable.

[nomel]

I can absolutely tell the difference between an early iPad Pro (20ms) and later (9ms), when using a pencil. With the lower, it feels more like paper, like color is coming out of the pencil.

[TheRealPomax]

"Close"? Anything over 3~4ms starts to be noticable, and anything over 10ms is "clearly" noticable for folks who expect the response of a pencil on paper.

[TheRealPomax]

That's not an "only", that's still at least twice what it needs to be to cross the uncanny valley of input latency.