When I actually went to the source for the 240hz claim, I didn’t reach the same conclusion as the testers?
Maybe they just let their rigol scope spit out 240hz, but 480hz worst case and I would actually say 960hz. I think what’s happening with the tandem oled is they both pwm at 480hz and 180 degrees out of phase giving effective 960hz when both are in use. Which appears to be most of the usable brightness.
Edit: I’m so confused.
“The PWM behavior is interesting, because we can see DC-dimming for all brightness levels. Usually, OLED panels use DC-Dimming only at higher brightness levels. The frequency is very low at 240 Hz, however, and this might be an issue for sensitive users, despite the DC-dimming. ”
https://www.notebookcheck.net/Amazing-OLED-panel-Apple-MacBo...
If it’s as low as 240hz, anyone will see a stop motion effect by waving an open hand in front of the screen at 50% brightness.
I’m curious if this is a harmonic mode for a high speed PWM where pulses are either not even widths or the driver loses some power at the 240hz cycle. May perceive similarly.
I have a couple windows laptop workstations with high dpi OLEDs (one with 240hz refresh rate) that I love and don’t perceive this so I’ll have to check.
I have one of these laptops, I tried waving my hand in front of the screen at 50% brightness and I don't observe anything unusual.
I think I am pretty insensitive to this effect, though. Other than occasional seeing a bit of 60 Hz flicker out of the corner of my eye from Christmas lights, automotive LED tail lights, etc. I don't tend to notice flicker.
I am shocked that Apple would release a screen with such a low PWM frequency. Here is a paper showing humans can perceive flicker at frequencies more than double their display’s rate: https://www.nature.com/articles/srep07861
As someone who’s had a concussion, this is really interesting. For me this is how any screen was to me, not just bright OLED ones. Even more interestingly it’s essentially only screens— backlist posters at the mall (paper with a backlight) still affect it but less so. To me perhaps it’s focusing on something on a screen that does this, but it’s really interesting to see this affect the general population.
It’s also odd to think about lack of ability to concentrate, and I wonder if screens cause this optically somehow but to a less noticeable degree even when less intense than this new one? (Independent distracting contents)
I noticed that adding a severe red filter to all my screens helped me significantly with the concussion and am also curious about that, would that impact the intensity of a refresh perhaps? Is blue light specifically the problem? I’m unsure but have a plethora of subjective experience.
I’m glad for this to enter public consciousness a bit and would love to see more research on the screen itself impacting our brain.
curious; do you mean like a red plastic see-thru filter applied on top of the screen (filtering the backlight too, like those screen protectors), or a software screen effect that makes everything on screen appear red?
red/blue/green (cones) in our eyes use different paths and have different "refresh rates" than luminous intensity (rods), im wondering if filtering to a single color makes the cones take over
I'd be fascinated to see how common this really is. Is it something that affects .0001% of users, more, less? At Apple scale an issue like that could hit millions of people. Given the newness and expense of the product one would assume not that many OLED Macbook Pros have shipped. So it's surprising that this issue didn't come up in testing if we're talking about more than a handful of people.
Given that we discovered in the nineties that CFL tubes were unhealthy for a significant portion of the population at these refresh rates and changed to over 30kHz I would assume the same holds true here. In other words: more than we would have thought.
It's hard to put a number on it (e.g. do people with eyesight problems or headaches actually know it's their display?) and it may also be influenced by other factors. I have used phones with 240Hz PWM dimming for years and haven't had an issue. However, I quickly get eyestrain when looking at e.g. a Samsung S26 Ultra. It's probably the combination of 240Hz PWM, FRC for emulating 10-bit on an 8-bit panel, and maybe the two types of pixels (narrow and wide, for the privacy display) that makes it painful for me.
I can also imagine that lower frequency PWM dimming can be more problematic on a display that covers a larger portion of your sight. Many people also probably use their laptop/computer screen for a longer time without looking away (aside from phone addicts).
A small aside: this is why I truly hate when people argue 'oh well, his only happens in 1% of cases, it's not worth supporting/solving'. With sufficient scale, and even without sufficient scale, it's thousands or even millions of people!
PWM sensitivity has been an issue on the iPhone for a long time, but the prevailing wisdom is that it affects only a small percentage of users, and then only at certain lower brightness levels. Consider it like a food allergy, we don’t rearchitect the entire food supply for everyone around the sensitivities of a few.
That said, I have my doubts about prevailing wisdom being true here.
I'd love for more research to be made into PWM sensitivity, if only to find out roughly how many people experience problems with it.
I've never had issues with it other than when trying to film certain old displays, but then again, I've never had issues with PAL TV sets running at 50 hz interlaced, nor even old PC CRTs running at 60, which definitely was not 'flicker-free', so I'm probably on the far end of the spectrum compared to the PWM sensitive.
It's an easy thing to forget, as with many accessibility features. And it's going to suck to have the nominally best display be one you just can't use if want to not feel like gouging your eyes out.
I notice PWM all around me all the time. Lots of cheaper LED lights use it, and I see it whenever I move my eyes, also when not consciously looking for it - instead of a blur I see series of lamps as a brief afterimage.
As a child I got headaches from CRT monitors at 60hz and I could see them flicker. I haven't noticed the PWM on modern monitors, but maybe these Apple ones would trigger me?
I was expecting to read this and learn that the display was reasonably engineered and that there is some small subset of people who have extreme PWM sensitivity who have problems. But no, Apple modulates at 240Hz, according to plenty of articles.
We’re no longer in the dark ages of flicker. There’s actual industry guidance: IEEE 1789. And 240Hz, at any respectable depth of modulation, does not meet the low-risk limit, let alone the no-observable-effect limit.
I am wondering whether this is actually just an amazing firmware goof: the reports seem to suggest that operating at full brightness mitigates the problem, which makes little sense for an OLED display. An OLED showing 50% (post-gamma) gray ought to drive the pixels the same way as an OLED at 50% brightness showing white. And this display supports HDR, so even 100% brightness white isn’t really 100%.
I’m wondering if a little engineering mistake snuck in: some (most?) LCD displays dim by PWM-dimming the backlight, and plenty of backlights have current-to-light transfer functions that inherently low-pass filter the light. If someone naively ported the same logic to an OLED (which doesn’t have a backlight), they might have implemented brightness controls by applying a 240Hz envelope to the pixel excitation waveform. This makes no sense at all as an actual implementation, but I can totally see an AI doing it and writing tests to validate it :)
Even if there is a genuine engineering factor that requires low frequency PWM, I bet Apple could mostly mitigate the problem by deliberately mismatching the phases. For decades, pre-LED stadium lights had rather extreme flicker at 120Hz, but it was tolerable because the overall system was engineered to roughly evenly split the lights between three electrical phases, giving an effective modulation depth near zero.
I haven’t seen one of these displays myself. I find 120Hz flicker to be extremely obvious and very very unpleasant, and if these displays really do modulate in a nasty way at 240Hz, I expect I’ll be able to see it, albeit rather less obviously than at 120Hz. Also, pretty much any modern phone can see this in slo-mo video mode :)
I had to return the Steam Deck OLED and LCD because their displays PWM was burning my eyes out. Sore eyes for days, having problems to focus properly. I hope this is a learning process and it will get better from the manufacturer side. But I hoped that after my personal Steam Deck fiasco as well.
The shell is 1:1 to a mbp. I predict the following things will happen.
Water damage- folks using their semi dry hands to touch the screen- that water is going to drip straight down to the logic board!
Injury- those sharp corners at the top of the keyboard are just waiting for a power user to swipe.
Screen separation. Touch screens were made with durability in mind- the hinge on the touchscreen mbp is identical in range to the stock mbp. Can’t wait till gen 2
I am not particularly sensitive, but switching the ipad pro for the oled model, I just don’t like the screen that much, and it is hard to put the finger on why. Side by side, the screen has better blacks and peak brightness and I am sure it beats the LCD empirically on many metrics. But I don’t like the colors as much, and perhaps subconsciously, the flicker is turning me off.
Seriously cannot believe the PWM frequency is 240Hz. I was shocked out of my mind when I first saw that. It needs to be on the order of kHz to avoid eyestrain for a very significant proportion of the population. Did Apple just forget about accessibility, or did they underestimate it?
PWM frequency is not selected in a vacuum. The maximum is set by your transition time which is set by a bunch of other engineering decisions. It's possible that something about tandem OLEDs make them more difficult to drive faster edges on.
Do slower pixels prevent you from using a higher PWM frequency? Wouldn't that make them like a capacitor smoothing out the high frequency signal into a constant one, like in a Class-D amplifier? That would reduce strobing even more!
Slight aside. I was thinking of buying a Google Pixel 11 but I learned that they have the same problem. I will go into a store and see if the Pro version (which can do 480 Hz) is OK.
Even if I'm not sensitive I am wary of this, what if it causes subtle eye strain that has long-term consequences?
OLEDs commonly flicker at some small multiple of the refresh rate because they often use something somewhat similar to DLP bit-plane modulation to avoid non-linearity at low brightness. You can't do that at xy kHz because that would require xy kHz scanout to the panel, which is physically ... not very plausible. You can gate drive current, but then you're back to how a 2010 LED backlight operates.
TIL there’s a pretty serious downside to OLED. Love the contrast ratios but not this.
I’m not super sensitive to flicker but can be annoyed by it. I’ve used OLED phones but it’s probably not as annoying on a small screen than one that covers more of your visual field.
If you go in a dark room and set the brightness of an OLED phone to minimum and then just swing it around in front of your eyes you're very likely to see a stroboscopic effect. For iPhones this seems to become noticeable below about 20-30% brightness.
I Think Apple gets progressively worse and worse and I mean in a general way. There are some anomalies there and there but overall the direction is a slow decline in details and quality.
I love me some high end electronics that doesn’t feel cheap but soon it will be not worth it.
It’s still many times cheaper to overhaul Apple than to start another company from scratch.
They still have the right ethos, philosophy and past traditions engraved in the History of the company. Someone just needs to remind them what are they supposed to be doing.
The problem isn't the flicker directly (240Hz is above the flicker fusion threshold), it's the phantom array effect when you move your eyes. Static images transform into a series of overlapping images, and this can be annoying and distracting. It's visible well into the kilohertz depending on how strong your saccadic masking is. I can personally see PWM up to about 10kHz (tested using a strobing LED).
AFAIK, all OLED displays have PWM flicker, and for this reason I stick with LCD, where flicker-free displays are available (although PWM flicker is present in some LCD displays too).
It's not about whether you can "see 240Hz". CRT phosphors have sustain, while OLED does not. The fully-on, fully-off cycle, if infrequent enough, causes some sort of visual stimulation that some brains absolutely do not like. You don't have to see it to feel it.
Sometimes I can tell flickery fixtures because they just "feel more staticky". I don't get visual eyestrain or nausea though.
Other than some old monochrome CRTs, all CRT phosphors decay too fast to prevent flicker. You get some softening of the trailing edges of the phantom array images, but they're not actually blurred together like on a sample-and-hold display. And even the fastest CRTs have fairly low refresh rates, making it more obvious.
This is one of the worst articles in terms of information per word density! Too many words and so much beating around the bush before it even discusses what the heck it's talking about.
> But some people are particularly sensitive to this kind of modulation and can experience eye strain, headaches and other forms of discomfort when looking at displays that use it.
So that tiny fraction of users would be well served with some other display and can either return their MacBook or use an external monitor if and when they find out that they're in that cohort.
Maybe they just let their rigol scope spit out 240hz, but 480hz worst case and I would actually say 960hz. I think what’s happening with the tandem oled is they both pwm at 480hz and 180 degrees out of phase giving effective 960hz when both are in use. Which appears to be most of the usable brightness.
Edit: I’m so confused.
“The PWM behavior is interesting, because we can see DC-dimming for all brightness levels. Usually, OLED panels use DC-Dimming only at higher brightness levels. The frequency is very low at 240 Hz, however, and this might be an issue for sensitive users, despite the DC-dimming. ” https://www.notebookcheck.net/Amazing-OLED-panel-Apple-MacBo...
I’m curious if this is a harmonic mode for a high speed PWM where pulses are either not even widths or the driver loses some power at the 240hz cycle. May perceive similarly.
I have a couple windows laptop workstations with high dpi OLEDs (one with 240hz refresh rate) that I love and don’t perceive this so I’ll have to check.
I think I am pretty insensitive to this effect, though. Other than occasional seeing a bit of 60 Hz flicker out of the corner of my eye from Christmas lights, automotive LED tail lights, etc. I don't tend to notice flicker.
It’s also odd to think about lack of ability to concentrate, and I wonder if screens cause this optically somehow but to a less noticeable degree even when less intense than this new one? (Independent distracting contents)
I noticed that adding a severe red filter to all my screens helped me significantly with the concussion and am also curious about that, would that impact the intensity of a refresh perhaps? Is blue light specifically the problem? I’m unsure but have a plethora of subjective experience.
I’m glad for this to enter public consciousness a bit and would love to see more research on the screen itself impacting our brain.
red/blue/green (cones) in our eyes use different paths and have different "refresh rates" than luminous intensity (rods), im wondering if filtering to a single color makes the cones take over
I can also imagine that lower frequency PWM dimming can be more problematic on a display that covers a larger portion of your sight. Many people also probably use their laptop/computer screen for a longer time without looking away (aside from phone addicts).
I’m all about hyperbole, but that’s a bit ridiculous.
That said, I have my doubts about prevailing wisdom being true here.
I've never had issues with it other than when trying to film certain old displays, but then again, I've never had issues with PAL TV sets running at 50 hz interlaced, nor even old PC CRTs running at 60, which definitely was not 'flicker-free', so I'm probably on the far end of the spectrum compared to the PWM sensitive.
It's an easy thing to forget, as with many accessibility features. And it's going to suck to have the nominally best display be one you just can't use if want to not feel like gouging your eyes out.
1. CRT display phosphors had afterglow.
2. the cathode ray was a dot moving across the screen, that might be easier on eyes than whole OLED screen flashing at once.
As a child I got headaches from CRT monitors at 60hz and I could see them flicker. I haven't noticed the PWM on modern monitors, but maybe these Apple ones would trigger me?
We’re no longer in the dark ages of flicker. There’s actual industry guidance: IEEE 1789. And 240Hz, at any respectable depth of modulation, does not meet the low-risk limit, let alone the no-observable-effect limit.
I am wondering whether this is actually just an amazing firmware goof: the reports seem to suggest that operating at full brightness mitigates the problem, which makes little sense for an OLED display. An OLED showing 50% (post-gamma) gray ought to drive the pixels the same way as an OLED at 50% brightness showing white. And this display supports HDR, so even 100% brightness white isn’t really 100%.
I’m wondering if a little engineering mistake snuck in: some (most?) LCD displays dim by PWM-dimming the backlight, and plenty of backlights have current-to-light transfer functions that inherently low-pass filter the light. If someone naively ported the same logic to an OLED (which doesn’t have a backlight), they might have implemented brightness controls by applying a 240Hz envelope to the pixel excitation waveform. This makes no sense at all as an actual implementation, but I can totally see an AI doing it and writing tests to validate it :)
Even if there is a genuine engineering factor that requires low frequency PWM, I bet Apple could mostly mitigate the problem by deliberately mismatching the phases. For decades, pre-LED stadium lights had rather extreme flicker at 120Hz, but it was tolerable because the overall system was engineered to roughly evenly split the lights between three electrical phases, giving an effective modulation depth near zero.
I haven’t seen one of these displays myself. I find 120Hz flicker to be extremely obvious and very very unpleasant, and if these displays really do modulate in a nasty way at 240Hz, I expect I’ll be able to see it, albeit rather less obviously than at 120Hz. Also, pretty much any modern phone can see this in slo-mo video mode :)
I had to return the Steam Deck OLED and LCD because their displays PWM was burning my eyes out. Sore eyes for days, having problems to focus properly. I hope this is a learning process and it will get better from the manufacturer side. But I hoped that after my personal Steam Deck fiasco as well.
If you want to use PWM in an application like this you need to start at like 600hz. This is how fast the subfield drive on a plasma TV is.
I have to use incandescent lightbulbs for certain fixtures because I sometimes need a break from engineers who think they are smarter than me.
To this day on macOS, the font size accessibility setting only works on first-party apps!
Even when using Apple's own UI frameworks, and using semantic font sizes that do actually scale up and down on iOS / iPadOS
It astonishes me!
https://www.notebookcheck.net/The-new-Tandem-OLED-panel-in-L...
Even if I'm not sensitive I am wary of this, what if it causes subtle eye strain that has long-term consequences?
This: https://www.notebookcheck.net/fileadmin/Notebooks/Apple/MacB... is perceptually very different from a low frequency low duty cycle PWM you'd get out of a cheap LCD backlight.
All OLED iPhones flicker below some brightness threshold, for example.
I’m not super sensitive to flicker but can be annoyed by it. I’ve used OLED phones but it’s probably not as annoying on a small screen than one that covers more of your visual field.
I love me some high end electronics that doesn’t feel cheap but soon it will be not worth it.
They still have the right ethos, philosophy and past traditions engraved in the History of the company. Someone just needs to remind them what are they supposed to be doing.
Like CRTs scan slower than that, and almost no-one could say they could see the pixels being drawn.
Sure you could hear those fuckers, but not see them, unless you had a source of vibration nearby.
Howe much of this is measurable, and how much of it is similar to the Himalayan salt lamp stuff?
AFAIK, all OLED displays have PWM flicker, and for this reason I stick with LCD, where flicker-free displays are available (although PWM flicker is present in some LCD displays too).
Sometimes I can tell flickery fixtures because they just "feel more staticky". I don't get visual eyestrain or nausea though.
Other than some old monochrome CRTs, all CRT phosphors decay too fast to prevent flicker. You get some softening of the trailing edges of the phantom array images, but they're not actually blurred together like on a sample-and-hold display. And even the fastest CRTs have fairly low refresh rates, making it more obvious.
It's not magic. :) You DO see it. 500 Hz for the median observer; above 800 Hz for some individuals. https://doi.org/10.1038/srep07861
There is still some ability to percieve strobing at a steady state though, even if the amplitude is reduced by visual persistence.
OLED plus dark mode is a way to juice advertised battery life.
> At 240Hz, the brightness fluctuation repeats 240 times per second; at 14,880Hz, it repeats almost 15,000 times per second.
Was that written for people who don't know what "Hz" means, or who don't know that 14880 is almost 15000?
For example, could we overlay a software dimmer while driving the panel at max brightness?
Or would it be possible to tune PWM settings from the OS?
Or would this be possible to tune with a firmware change?
Idk how these things work.
So that tiny fraction of users would be well served with some other display and can either return their MacBook or use an external monitor if and when they find out that they're in that cohort.