I was just sitting in front of my computer, watchin' Keith Olberman (yeah, there is a TV tuner in my computer monitor :-) and I thought I would try cleaning my circular polarizer while I'm sitting here. Well, I just happened to hold it up in front of my screen, and... cool! Try it both ways; looking at the screen through the filter from back to front, turning of course, and then look from front to back, too. Nothing dramatic, but very unexpected, to me!
Yeah, who knew a monitor was so intensely polarized, it goes black through a CPL!
Now, how come when you turn the polarizer around and look through front to back, the effect is just a faint shift from yellow cast to blue cast, but the it hardly darkens at all?
Roy Pertchik wrote:
Yeah, who knew a monitor was so intensely polarized, it goes black through a CPL!
Anyone that understands how an LCD display works for the last 25 years?
Now, how come [sic] when you turn the polarizer around and look through front to back, the effect is just a faint shift from yellow cast to blue cast, but the it hardly darkens at all?
Because it is a circular polarizer, not a linear polarizer. The CP has an additional layer (1/4 wave retardation) after the linear polarizer that changes the phase of polarization. The camera needs to "see" circular polarized light for the AF and metering to function properly.
EB-1 wrote:
[
Anyone that understands how an LCD display works for the last 25 years?
not me :-)
.....The CP has an additional layer (1/4 wave retardation) after the linear polarizer that changes the phase of polarization.
This I knew, except for what it means! ..."changes the phase"... like the troughs become peaks and the peaks become troughs? ... but, why does that make it work so differently? You can exchange the troughs and peaks of a normal polarizer by moving it half a cycle (1/4 cycle?), can't you.... yeah, I know some of this, but it's light stuff in the quantum realm, so no one ever really "groks" it...
Anyway, it's a cool effect. For those of you who have never tried it, seen it, thought about it, give it a try and let me know if you think so too.
as a Avionics tech on commercial aircraft i made that discovery that my particular favorite set of sunglasses (nikon) was nicely polarized. when my outfit first got the B777 i walk into the all glass (LCD monitors) flight deck with a crew doing preflight. they're just mulling about putting in flight data that wasn't downlinked to them and i'm standing at the door looking at to me was blank screens. as they had called me out for an issue i immediately assumed the worst case scenerio. and immediately jumped to troulbeshoot what i saw. i whipped off my glasses and instantly my point of view changed to reality. captain turned to me and asked " sunglasses polarized?" and i answerd "never realized it but does seem to be the case". my heart rate came back down to a more reasonable level and they had a good laugh at my expense. they had originally called me out for a loose knob on a panel.
