[waxjar]

I used to have the same issue as you.

F.lux emulates an undergoing sun. That doesn't happen in 20 seconds. Set the transition time to Slow.

Also select the right type of lighting. If none of the types match your lighting, juggle a bit with the settings until your screen looks the same way a piece of paper would look in the same lighting.

If you do that, you won't notice it's running at all. The only reason I turn it off is when I'm watching a movie. The colours in a movie usually already take darkness in account.

[jonnytran]

I wish there were some way for it to detect the ambient light of the room I'm in. Late at night I prefer the warmest setting. But I feel like I'm constantly adjusting f.lux based on where I am. If I'm out, I can't control the lighting of the room. At home in the winter when it gets dark early, I don't want to turn the lights off at 5pm. But if I don't adjust f.lux, it hurts my eyes.

For the most part, though, I think it's great.

[nitrogen]

My grandfather had an ancient color TV with this feature. You could press a toggle button on the front that would open or close an iris over a sensor, and the TV would adjust the on-screen color to match the room lighting.

[Avshalom]

As long as it can be set by command line or has a simple config file it shouldn't be that hard to set up a daemon to take a picture with a webcam then munge the color temp and brightness and adjust f.lux accordingly.

[mikepurvis]

It would be neat if it could auto-calibrate based on a reference image of what you look like sitting in front of your webcam.