A chance to talk to FlatpanelsHD's reviewers.
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By Rasmus Larsen
People sometimes ask me if modern LED based LCD TVs still use PWM to modulate the backlight brightness level. Some people perceive PWM as very high-frequency flicker.

So I checked for PWM on both Panasonic EX700 and Sony X85E (review coming later this week).

As you can see in the photo below, Panasonic EX700 does indeed use PWM. The photo was shot with a 1/25 sec exposure time and there are 10 lines so PWM operates at 10*25 = 250Hz.

By AndreaCepo
Does the calibration posted in the review works for only 'normal' video television mode or hdmi mode (e.g. Sky TV box) too? The only difference you suggest between day and night view is to switch on/off the ambient sensor?
And one more question : do you suggest different settings for watching a movie or watching sports, for example football?
I have this television since few days, it's my first smart TV (so I'm an absolute newbie) but I have the impression that the quality of image changes a lot between day and night, and even if you watch a movie rather than a football game..

Off topic : do you suggest a light at back of TV for a dark room, for example led lights?

Any suggestions, helps and settings of the users are welcome!

Thank you,

User avatar
By Rasmus Larsen
Both the built-in tuner and via HDMI. As long as your playback devices conform the the standard a calibration is universal - also for sports. Some people prefer to engage the motion system (IFC in Panasonic's case) when watching sports but that should be the only different.

Yes, the ambient sensor can help adjust the picture, but it's not perfect. Consider it a way to ensure that the TV's backlight increases as the light in your environment go up. Our calibration settings would be too dark for daytime viewing.

According to some studies bias lighting can help the eye relax and enhance the perception of contrast on LCD TVs viewed in dark rooms, but I guess it is a matter of taste. Personally, I don't use bias lighting.