Frontlight brightness control question

[RodRiquez]

Hi, I currently have a Kobo Clara HD & have been looking to upgrade to something with snappy PDF performance.

There are several Boox models im excited about : Tab mini c, go color 7, Page
(I dont need color, but its tempting) They all look amazing.

Anyway, I have a question about the Frontlight that I was alerted to watching YT video.
The Boox frontlight doesnt have precise control & even the minimum setting is quite bright.

My Kobo Clara goes from 0-100%. Every night I read in bed & have it set to 8%
I find 6% is too low & 10% is too high. Having that precise control on the light is a super important point for me.

The video was a couple of years old, so maybe things have changed. Can you confirm the frontlight operation for me?

[Renate]

I find that lots of readers don't have good fine control of brightness/color temperature. The problem is not the hardware itself but not having all steps in the controls having the same apparent effect. Most every device, Eink or other, uses the same LM3630A LED driver. But this gets mapped to some OEM specific values for some OEM specific settings. I wrote my own little app with big sliders and plenty of steps. Still, it has to handle all the different software schemes of all the different devices.

Let's put it this way, I usually leave my backlight at "30%" on my scale all the time. If it's dark, I notice that, if it's bright, I don't. The power consumption at that level isn't worth worrying about.

[RodRiquez]

Ok, thanks.

The only thing I am concerned about is that if the minimum brightness setting on Boox is equivalent to 10% or more of Kobo Clara then the Boox will be unusable for me.

This is simply because 95% of the time I read in bed in total darkness.
If its bright enough for my wife to notice then .... !

On Kobo the brightness controls have a slider, but also (+ -) buttons to adjust in 1% increments.

[Aleron Ives]

Even if you can control the Boox frontlight in 1% increments, there's no guarantee that 1% on the Page is the same as 1% on the Clara. Somebody would need to test both devices side by side to find out.

[RodRiquez]

Yep. Im hoping someone will be able to answer that. A lot of people in these forums have multiple devices.

Ive narrowed my options down to Boox Page.
The reviews show it as snappy & capable.

• Does the Page have (+ -) buttons to adjust the brightness in 1% increments?
• If you go into a totally black room / closet & set to 1%, is it a struggle to read the text? - that would be a good indication that the minimum isnt too bright.

[Renate]

The LM3630A is logarithmically controlled so there is plenty of range. Your eye is also logarithmic. Sunlight is about 10,000 brighter than moonlight, but you can read a paper book by good moonlight. The problem is mostly the step from off to minimum brightness built into the user interface. I find the maximum brightness on most devices absurd.

The logartihmic step is 1.028 brightness. You can barely see that even if it switches up and down while you're looking at it. That's in a range of 0-255. Most software reduces that to 0-100% as an integer which is already throwing away resolution. The inherent range of brightness of the chip is about 1240.

Originally Onyx had a two slider control but it was for warm LED and cold LED. It was impossible to control brightness and get the color temperature right. I wrote an app also with two sliders for brightness and color temp. Since then, Onyx got its act together and I haven't used that app.

So here's my Go6 at 5% brightness. It's not really bright enough for the camera on my phone to focus.