Forma New Kobo reader: The Forma/Shape

[Barcey]

Originally Posted by Jason90

can someone please confirm if the kobo forma by design using PWM (pulse width modulation) for the light as seen in this video?

This is a deal breaker for me if the case as pwm is the bane of lcd tech!

I hadn't noticed this so out of curiosity I tried this on my Forma, recorded slo mo on iPhone 7 in the dark with brightness at 100% and I don't see this flickering. I also tried it side by side with my Aura One and don't see flickering on either.

[ivanvt]

Can anyone tell me if the Forma has a light sensor to increase/decrease the LEDs? also does it automatically turn on the orange LED (Night mode) like KA1 ?

[jackie_w]

Originally Posted by ivanvt

Can anyone tell me if the Forma has a light sensor to increase/decrease the LEDs? also does it automatically turn on the orange LED (Night mode) like KA1 ?

There isn't an auto-brightness setting. There is an auto-colour-temperature setting which you can enable/disable as you prefer.

[Calenorn]

Originally Posted by jackie_w

There isn't an auto-brightness setting. There is an auto-colour-temperature setting which you can enable/disable as you prefer.

... but if it's like the Clara then it operates on time. The Clara does not have a light sensor.

[MGlitch]

Originally Posted by Calenorn

... but if it's like the Clara then it operates on time. The Clara does not have a light sensor.

Which is the same way the KA1s ComfortLightPRO option works. The only thing the light sensor controls is the white LED light, not the orange ones.

[rashkae]

Originally Posted by Calenorn

... but if it's like the Clara then it operates on time. The Clara does not have a light sensor.

The A1 also operates on time, (with regards to colour temp.) contrary to the many, many GoodEReader videos that claim otherwise.

[Jason90]

Originally Posted by Barcey

I hadn't noticed this so out of curiosity I tried this on my Forma, recorded slo mo on iPhone 7 in the dark with brightness at 100% and I don't see this flickering. I also tried it side by side with my Aura One and don't see flickering on either.

Well i have some very bad news for people who wish to purchase the forma.

Got my device today thinking the guy in the video i posted earlier must of just had a faulty device and i did a 240fps iphone slo-mo record just like him and mine is doing exactly the same thing!

Here's my kobo: https://youtu.be/B8Oc3FcizyY

It does this on all brightness levels except with brightness and natural light both at 100%,i.e when all the leds are on.

As far as i understand this is PWM (Pulse width modulation) which is the worst culprit of eye fatigue and headaches ,totally beats the point of an ereader!

Kobo have really screwed up here as the design of the device itself is the best of any ereader i have purchased in the past and i'm quite saddened by this!

A part of me really wants to keep it but as i do alot of reading at night i can't keep the device at 100% brightness so it's going back i'm afriad.

I'm thinking of making a seperate post about this as i know people buy ereaders because they want a comfortable reading experiance and this has ruined the kobo forma!

[k9reeder]

Originally Posted by Jason90

Well i have some very bad news for people who wish to purchase the forma.

Got my device today thinking the guy in the video i posted earlier must of just had a faulty device and i did a 240fps iphone slo-mo record just like him and mine is doing exactly the same thing!..

Here's a link to that earlier video for comparison:


A second poster on reddit also reported seeing the lines, in slo-mo, going vertically across, as in your video, rather than up and down, but that might be an artifact of the different cameras being used.

I've had some extended reading sessions with the Forma using the lights and so far haven't had any ill effects, but perhaps I'm not as susceptible as others.

[Jason90]

Originally Posted by k9reeder

Here's a link to that earlier video for comparison:


A second poster on reddit also reported seeing the lines, in slo-mo, going vertically across, as in your video, rather than up and down, but that might be an artifact of the different cameras being used.

I've had some extended reading sessions with the Forma using the lights and so far haven't had any ill effects, but perhaps I'm not as susceptible as others.

It's true not everyone is perceptible to flicker/pwm but i'm pretty sure it's still doing something negative to your eyes.

Thanks for confirming that this is now obviously by design and not a technical fault,the fact that it doesn't happen on 100% brightness already confirmed it was pwm to me anyway as almost all devices such as laptops ect that use pwm normaly stop flickering at 100%.

As someone who avoids pwm like the plague i am not only annoyed the forma has flickering but now that it has entered the eink arena any devices from here on out are going to have to be tested for this before i consider purchasing one.

[jackie_w]

Originally Posted by Jason90

I'm thinking of making a seperate post about this as i know people buy ereaders because they want a comfortable reading experiance and this has ruined the kobo forma!

When you do please include a poll so that we can ascertain what percentage of Forma users are able to detect any flicker at all - at any light level, at any colour.

Speaking only for myself, if the only way I'll be able to see any flicker is by taking a slow-mo video of the screen then I'm willing to take my chances and stick to reading the screen directly rather than via video.

Come to think of it, as I've been looking at screens for many hours per day since I was 21 years old, my eyes are probably doomed anyway.

[Jason90]

Originally Posted by jackie_w

When you do please include a poll so that we can ascertain what percentage of Forma users are able to detect any flicker at all - at any light level, at any colour.

Speaking only for myself, if the only way I'll be able to see any flicker is by taking a slow-mo video of the screen then I'm willing to take my chances and stick to reading the screen directly rather than via video.

Come to think of it, as I've been looking at screens for many hours per day since I was 21 years old, my eyes are probably doomed anyway.

Will do,the problem isn't that you can actually 'see' the flicker but that it is going on subliminally,you might not notice it straight away but after time it tires your eyes out and for some gives them headaches.

See even when i look at the forma screen at less than 100% brightness compared to 100% brightness i can sense the flickering and staring at this for long peroids of time will do my eyes in

[DNSB]

Originally Posted by MGlitch

Which is the same way the KA1s ComfortLightPRO option works. The only thing the light sensor controls is the white LED light, not the orange ones.

On my KA1, the light sensor seems to control both the white and coloured LEDs brightness.

[murraypaul]

Originally Posted by DNSB

On my KA1, the light sensor seems to control both the white and coloured LEDs brightness.

But the colour of the LEDs (how yellow/orange they get) is controlled by a timer, not by the light sensor.

[DNSB]

Originally Posted by Jason90

It does this on all brightness levels except with brightness and natural light both at 100%,i.e when all the leds are on.

As far as i understand this is PWM (Pulse width modulation) which is the worst culprit of eye fatigue and headaches ,totally beats the point of an ereader!

Interesting. It should not be doing PWM on 100% brightness even if natural light is at 0.

As for PWM causing eye strain, the studies I've seen suggest that about 10% of people are affected IF the PWM is running at too low a frequency. If the frequency is over 200Hz, I was unable to find a study that showed evidence of eyestrain.

Given the issues with LEDs and attempting to control brightness by current modulation, PWM is going to be used with virtually all LED lighting though some monitor manufacturers such as Asus are using a combined approach mixing PWM and current modulation.

[Jason90]

Originally Posted by DNSB

Interesting. It should not be doing PWM on 100% brightness even if natural light is at 0.

As for PWM causing eye strain, the studies I've seen suggest that about 10% of people are affected IF the PWM is running at too low a frequency. If the frequency is over 200Hz, I was unable to find a study that showed evidence of eyestrain.

Given the issues with LEDs and attempting to control brightness by current modulation, PWM is going to be used with virtually all LED lighting though some monitor manufacturers such as Asus are using a combined approach mixing PWM and current modulation.

Here is a fourm thread detailing peoples issues with pwm on the iphone x,the first iphone to use pwm as a result of using a oled panel at 240hz.

https://forums.macrumors.com/threads...one-x.2085427/

Don't know where you got the 10% figure from as that thread would suggest a significant percentage experience problems associated with flicker/pwm!