Carson microflip at 100-200x magnification. To clarify, it is getting hard to distinguish if what I'm seeing is pixel flicker or just artifacts and noise from my Samsung 240 fps phone camera. On crappy displays and monitors, the pixel flicker absolutely obvious and "undulating". With this display, it's actually a very good sign that I'm having difficulty making clear interpretations.
On pixelinversion.com and I did not see flicker on the first page of tests. Also a very good sign.
photon78s Opple waveform charts at 100%, 50%, and 25%
when I measure my 16" 2k 120hz laptop, I got results where Opple measure PWM freq equail to Screen refresh rate
At 120hz - 123hz PWM
At 60hz - 61hz PWM
At 50hz - 55hz PWM
At 48hz - 48hz PWM
I think, Opple dont show PWM coz it synchronise with refresh rate. And as lower brightness, as more noise in screen, so its hard to measure proper freq with Opple.
Look at your 25% measurments, dont you think its 8ms period and 120hz PWM?
Hmm... it is a fixed 60hz refresh rate screen correct for this model (no ProMotion, no miniLEDs)? Normally, you would think that refresh rate has nothing to do with the flicker of the backlight LEDs. I also film at 240fps (not with microscope) and don't see any backlight flickering. I agree on the noise as factor in general with any measurement. I also agree to not pay too much to the frequency numbers from the Opple and simply just get a rough sense of the waveform and how that might correlate with subjective comfort. Stay tuned for results with the oscilloscope and photodetector.
async It would be really interesting to do the same on an M2 Touch Bar with a bad screen.
There's not really a M2 Touch Bar with a truly "bad screen" / unusable screen IMO, since even my first one with the worse panel was still more usable than every other Apple Silicon Mac. It was more of just visible defects, yellow tint, and screen uniformity issues which made me return that one.
(The "worse" panel had long empty sections of 00000000 in the panel ID and serial number dump, the "amazing" panel has a fully filled out serial number without any empty sections.)
However, since I still have the M1 Air for a little bit longer, I will dump ioreg on there — since I consider the M1 Air very uncomfortable (relative to any M2 Touch Bar Pro).
The M1 Air's panel is a lot different, flickers on camera (in the same way the M2 Air does) and is way worse.
Will be interesting to see if the ioreg has any significant difference.
photon78s Edit: While I did not detect any PWM on the backlight at 240fps or at 1/24000 shutter speed photos the opple shows PWM flicker at lower brightness settings (see below). More testing on that later with oscilloscope waveforms.
Yep this lines up with the notebookcheck review (which is good to know, since sometimes notebookcheck can be really inaccurate)
When I say the M2 TB Pro screen is "flicker-free" I mean it's possible to make it flicker-free, i.e. at higher brightness levels.
Also, I actually did use the computer for a while at lower brightness levels yesterday, and whatever high frequency PWM is there still does not affect me nearly as much as the really annoying low frequency PWM-like flicker on M1 Air and M2 Air.
However, PWM can still be avoided at high brightness!
(Lots of people think that is true with other Macs too, but two 2015 Intel Macs I tested actually also show PWM-like flicker on dark grays in 240hz slow-motion even at max brightness!
M2 Touch Bar Pro is the only MacBook I've tested that just doesn't have this issue at all. This is what makes it so unique!)
And with Stillcolor, it's possible to dim the screen through color overlays or color table adjustments (e.g. with BetterDisplay) without introducing temporal dithering.
photon78s Can you upload a video of the "pixel flicker" you captured vs. the other laptops you recorded that have much worse pixel flicker?
photon78s Stay tuned for results with the oscilloscope and photodetector.
interesting fact: I have measured my old laptop display and Opple say no PWM (straight line), but I found panel datasheet where PWM is in 200…1000 hz range. I think it non-economical for laptop factory to set panel and replace build-in PWM backlight to backlight with LEDs which supports analog-type (voltage reducing) brightness adjustment
to get proper RGB pixel flickering video, you need at least 1000+ fps camera with ability to shoot at high ISO with 1/1000 shutter minimum, to capture at least 1000hz flickering frequency, or you get "smooth" results
photon78s It's still there but if this is in fact pixel inversion or some kind of FRC
I suspect that it's just pixel inversion because I don't seem to be getting any FRC or temporal dithering symptoms with this laptop at all.
These are the benefits that I get using the M2 Touch Bar Pro:
All of these I have much worse experiences on in temporally dithered screens (and I have problems with some of the above on the M1 Air too, so maybe the M1 Air still uses TCON FRC in some way?)
But on the M2 TB Pro, this all works so good for me, which is why I suspect whatever micro pixel flicker you are noticing is not temporal dithering.
Sampled on the same or close enough patch on blooey's test chart. Lenovo Legion Pro 7i at 60hz versus M2 MBP TB. I also suspect it is only showing pixel inversion differences at this point. The 7i is running ditherig.
Warning! Please do not click the link to watch the videos if you are or suspect you are sensitive to visible flicker!
photon78s Woww, that's an amazing difference compared to the 7i.
The 7i is definitely and obviously showing temporal dithering — but on the Touch Bar MBP, there's sooooo much less that I suspect that all that we're seeing there is mostly pure camera noise.
It doesn't seem to have a really noticeable pattern (compared to the 7i where dithering is clearly visible).
For example, I actually get something that is reminiscent of the remaining "flicker" on the Touch Bar MBP when recording even printed words on paper on my iPhone 14 Pro, which obviously shouldn't flicker, so I bet most of that is just camera noise.
That has been my reaction even since I got this cheap toy microscope looking at the differences between devices. Hope viewing the videos does not cause any further eyestrain as you said you are not sensitive to visible flicker!
photon78s Yeah the videos are totally fine to watch for me — I can literally watch a straight up flashing black to white strobe pattern on a screen and feel nothing at all LOL (in fact it sometimes even makes me feel better)
It's only the invisible & subliminal flicker that gets me
I should mention that I use the 7i at 240hz refresh rate. Whatever dithering or inversion that's there flickers faster (1/2 refresh rate for inversion) which for me is less straining (not for others). This is confirmed via scope video as well because of correct me if I'm wrong the Nyquist frequency and the limitations of 240 fps sampling rate.
DisplaysShouldNotBeTVs (Lots of people think that is true with other Macs too, but two 2015 Intel Macs I tested actually also show PWM-like flicker on dark grays in 240hz slow-motion even at max brightness!
Which ones exactly?
JTL flicker on dark gray at 240hz slow motion detected on these 2 Macs:
-
2015 15" Retina MacBook Pro (AMD dGPU, Core i7, 16GB), in both AMD and Intel graphics modes
12.6.8 Monterey
Personally, I don't like using this laptop, very uncomfortable, so much glare. I can notice temporal dithering, everything is shimmering (which cannot be fully solved with dither=0, even in Intel integrated graphics mode)
-
2015 12" MacBook (Intel HD Graphics, Core M, 8GB)
10.14.6 Mojave
Personally, this laptop is pretty good, very usable (although not perfect). Dithering can be successfully & noticeably disabled with dither=0. Image is very stable. However, I still get some "waves of tiredness" symptoms switching between light and dark content (like when switching browser tabs) which seems to be connected to this PWM-like flicker
My guess is that video takes a widely different route to the display, and bypasses at least some stuff. Just based on cpu/gpu/battery considerations it makes no sense to run as many types of image adjustments there. Not sure if this is the same as what is used in BetterDisplay. It would be interesting to test the following:
@waydabber You probably know much of this even without testing
DisplaysShouldNotBeTVs please how do you toggle on/off and test dither=0 on intel macs without the stillcolor app? Id like to try it. Mine is 15in 2018 with intel/amd graphics with Mojave.
reboot to recovery mode (hold Cmd+R while starting up before apple logo appears)
open terminal under the utilities menu
run the command nvram boot-args="dither=0"
reboot
this will only work in intel integrated graphics mode (force with gfxcardstatus app)
FWIW I have a 2018 macbook air that it doesn't work on at all (not even changing software brightness with betterdisplay will cause banding shifts, implying that it doesn't work at all), it's only ever worked for me succesfully on the 2015 12" MacBook. YMMV
if you really need AMD dedicated graphics dither disable method too, i can help you out later potentially, i know a more obscure method that lets you change without rebooting so you can actually see effects in realtime. if intel doesn't do anything, maybe AMD dither disable method will do something
fyi AMD method is neccessary for anything external monitor related. external outputs are hard-wired to AMD
too busy to share it right now though
however, on the one laptop I used AMD realtime dither disable method on — 2015 15" rMBP — despite noticeably changing how colors appeared it didn't actually fully remove the shimmering effect
(my theory is that 2015 15" has a "6-bit + FRC" panel that still tries to dither stable 8-bit GPU output)
maybe it would work better on P3 Wide Color MacBooks though like your 2018 15"
personally though, i've stopped messing around with dither disable methods recently because i'm literally in heaven now with my 13" M2 Touch Bar Pro with Stillcolor.
Literally has the most stable screen output I've ever seen on a Mac display. Better than any Intel Mac I've used and WAY better than everything else that has Apple Silicon. ALL other M1/M2/M3 stuff is unusable for me but specifically the M2 Touch Bar Pro is perfect — I am fully committed to it now LOL, not focused as much on improving my older Macs anymore
