iPhone 17 Models Include Toggle to Disable Screen Flickering (PWM)

[siksik6]

Where is the 50% number coming from?

Look at the screenshot above... 53 is the modulation percentage

 

[Jensend]

Look at the screenshot above... 53 is the modulation percentage

Can you explain what "modulation percentage" means?

 

[Jensend]

The wider the bars get the worse it is typically. What I’m hoping we’re seeing, and everyone is jumping the gun on, is something similar to oled tvs. All oled tvs are technically not flicker free with a slight dip that corresponds to the refresh rate but even folks extremely sensitive to pwm barely notice. This shows up as black bars on your tv as well.

Additionally, I believe oled monitors do this as well which is why they are often certified as flicker free by 3rd party companies.

My OLED TV only dips in brightness for about 0.15% of the the refresh time. The dip on my Pixel 8 Pro at full brightness is about 12.5% of the total refresh time (it has very similar PWM characteristics to an iPhone, from what I've seen).

 

[siksik6]

Can you explain what "modulation percentage" means?

Yep, so if 0 is the lowest screen brightness, and 10 is the highest, and the modulation is 100% that means that 480 times a second the screen is going from 0-10 on the brightness scale, increasing the 'strobe' like effect. A lower modulation (even with the same low flicker rate) is better on the eyes as the difference between the min and max brightness on every flicker cycle is less.

50% is still VERY high (Good OLEDs are already down below 10% like the Honor 200 Pro) so this isn't going to be much use to sensitive folk based on those numbers alone (if accurate of course)

 

[Jensend]

Yep, so if 0 is the lowest screen brightness, and 10 is the highest, and the modulation is 100% that means that 480 times a second the screen is going from 0-10 on the brightness scale, increasing the 'strobe' like effect. A lower modulation (even with the same low flicker rate) is better on the eyes as the difference between the min and max brightness on every flicker cycle is less.

50% is still VERY high (Good OLEDs are already down below 10% like the Honor 200 Pro) so this isn't going to be much use to sensitive folk based on those numbers alone (if accurate of course)

I think the testing methodology is broken. Almost all screens, including OLED, refresh from top to bottom (or a rotated version of that). The whole screen does not strobe at the same time.
I think what's happening here is that the light sensor covers an area, so it's reading some pixels that are 100% lit up, and others that are 0% lit up, and essentially taking an average.
Basically, the screens have narrow bands of pure black, but the testing sensor is mistaking them for slightly wider bands of less depth.

 

[Joelj]

So it doesn't disable PWM and it looks like the 17s are still a no go for a lot of us.

I can only hope the attention that's been drawn to the issue will have helped some people who weren't aware, and shown Apple that there is demand for a real solution. Also, Apple at least acknowledging it as a genuine accessibility issue for some people is still massive.

Hold out iPhone 11...

 

[Sheepish-Lord]

Results on the subreddit ‘Pwm Sensitive’ aren’t not promising.

 

[siksik6]

So it doesn't disable PWM and it looks like the 17s are still a no go for a lot of us.

I can only hope the attention that's been drawn to the issue will have helped some people who weren't aware, and shown Apple that there is demand for a real solution. Also, Apple at least acknowledging it as a genuine accessibility issue for some people is still massive.

Hold out iPhone 11...

Problem is for many of us the iPhone 11 doesn't work anymore since Apple insist on using loads of temporal dithering since iOS18 onwards... mine runs on iOS17 and it's 100% comfortable, my 'test' iPhone 11 is BAD on iOS26.

 

[DJTaurus]

Problem is for many of us the iPhone 11 doesn't work anymore since Apple insist on using loads of temporal dithering since iOS18 onwards... mine runs on iOS17 and it's 100% comfortable, my 'test' iPhone 11 is BAD on iOS26.

I did the mistake to update my 11 and i have headaches for f shake. How many days do I have to decide if to downgrade ?

 

[Joelj]

Problem is for many of us the iPhone 11 doesn't work anymore since Apple insist on using loads of temporal dithering since iOS18 onwards... mine runs on iOS17 and it's 100% comfortable, my 'test' iPhone 11 is BAD on iOS26.

I've actually been using my 11 more and more via iPhone mirroring these days for more comfort, I'm not sure if it's a result of iOS18 or just my general migraine/eye strain woes. So I'm definitely going to be cautious about any upgrade to iOS26.