Reducing LED brightness, F.lux vs monitor backlight



  • I noticed most monitors including my Dell UP2414Q seem to cause more eyestrain when the monitor brightness is reduced. I assume this is flicker from dimming the LCD backlight. Would keeping the monitor's internal brightness high while using f.lux to dim the display circumvent this type of flicker?



  • Yes that will solve the problem.

    I'm saddened that they would use such awful dimming technique on such a what would be a great monitor! What was Dell thinking?!

    http://www.tftcentral.co.uk/reviews/content/dell_up3214q.htm#panel

    Not the same monitor but the backlight dimming is the same. Your screen uses GB-r backlighting where as the one linked uses w-led which is not as good as yours.
    Your monitor does NOT use PWM, I was wrong.



  • It's due to the Pulse Width Modulation (PWM). The market has some "flicker-free" monitors now.

    Anyway, the dimming that is done by f.lux doesn't actually reduce your monitor's brightness at all. It just makes it produce more black. The color temperature gets warmer a little more each time you press Alt+Page Down, so keep an eye on that too.



  • ~~If you want a new monitor recommendation, I'll link you to BenQ's website.

    http://www.benq.us/product/monitor/GW2760HS/
    This is a seriously nice monitor. If you'd like more proof than just that sentence, you can go REALLY in depth with the following review by TFT Central.

    http://www.tftcentral.co.uk/reviews/content/benq_gw2760hs.htm#panel~~



  • Thanks for the input. The Dell UP2414Q is in fact a really beautiful monitor, albeit quite bright. It is also described as being zero PWM, but I suspect even DC/non PWM backlight can flicker below a certain threshold. It seems dimming with F.LUX solves the problem, I disable the "warmer as dimmed" option.



  • I've looked but I can't find any information on the backlight, I'm going to look at youtube with the monitor, then I can see it.

    EDIT: https://www.youtube.com/watch?v=k7KJyt6Z5yo
    Looks to not use an PWM, just DC controlled brightness. THERE IS NO PWM. DC dimming works perfectly, as you can see in the "recommendation" that you don't need, that I linked.

    I would say just turn down the brightness and use a camera (truly ANY digital camera, even on a phone, as they are quite good) to see if there is any flicker.



  • @MadMaxwell said:

    Thanks for the input. The Dell UP2414Q is in fact a really beautiful monitor, albeit quite bright. It is also described as being zero PWM, but I suspect even DC/non PWM backlight can flicker below a certain threshold. It seems dimming with F.LUX solves the problem, I disable the "warmer as dimmed" option.

    That option is only for when you dim a laptop monitor or a tablet monitor. When you use a laptop's or a tablets display dimming, f.lux can detect it and warm up the color temperature at the same time. When you dim a normal monitor (one that plugs into a computer), f.lux cannot detect it and so this feature doesn't work.

    So, it's not for when you press Alt+Page Up or Alt+Page Down. Not at all. It never was. Alt+Page Down will always warm up the color temperature because that's the way the program's code has been written and there's currently no option to tell f.lux to NOT touch the color temperature.

    Also, Alt+Page Down does not really dim your monitor. It just increases the black level. To see this for yourself, stick a white sheet of paper on your desk in front of your monitor. Now, turn all of your lights off and begin pressing Alt+Page Down. Keep going all the way to the dimmest setting. You will notice that even though it LOOKS dimmer, it is still producing the same amount of light. It's just blacker, that's all. The reason for this is, f.lux can't change the brightness of your monitor's backlight.


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