The local sandwich shop that I frequent recently switched to LED lighting. When I walk up to the counter I can see the flicker when people's hands are moving.
The same applies for LED taillights when a vehicle is moving as well as newer LED tower lighting. Bob On Sep 18, 2012, at 13:15, Hal Murray <hmur...@megapathdsl.net> wrote: > > li...@rtty.us said: >> There are a *lot* of TV's out there that refresh at 60 Hz or less. > > Many years ago, we had a busted fluorescent light at work. I could see the > flicker out of the corner of my eye. I found it annoying, so I'm a firm > believer that some people can see flicker in some conditions. (Fortunately, > it was in a location where I didn't spend much time.) > > Direct vision was not a problem. I assumed the lamp was running at 60 Hz > rather than 120 and that peripheral vision was better at detecting > flicker/motion. > > > Wiki has an interesting page on this stuff: > http://en.wikipedia.org/wiki/Flicker_fusion_threshold > > the rod cells of the human eye have a faster response time than the cone > cells, so flicker can be sensed in peripheral vision at higher frequencies > than in foveal vision > > But also: > The maximum fusion frequency for rod-mediated vision reaches a plateau at > about 15 Hz, whereas cones reach a plateau, observable only at very high > illumination intensities, of about 60 Hz > (I think that is backwards from the previous line. I'd guess somebody typoed > rods-cones.) > > Note that LEDs without diffusion are high-illumination, so I'm not surprised > if some people report flicker troubles. It would be interesting to > investigate some examples. I wonder if they are 120 Hz or 60 Hz? > > > More wiki: > > For the purposes of presenting moving images, the human flicker fusion > threshold is usually taken as 16 hertz (Hz). In actual practice, movies are > recorded at 24 frames per second, and TV cameras operate at 25 or 30 frames > per second, depending on the TV system used. > > Even though motion may seem to be continuous at 25 or 30 frame/s, the > brightness may still seem to flicker objectionably. By showing each frame > twice in cinema projection (48 Hz), and using interlace in television (50 or > 60 Hz), a reasonable margin of error for unusual viewing conditions is > achieved in minimising subjective flicker effects. > > > > > -- > These are my opinions. I hate spam. > > > > > _______________________________________________ > time-nuts mailing list -- time-nuts@febo.com > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.