Never heard of such
My student was wearing polarizing sunglasses. The rear lens on the EOTech is plane-polarized, necessary for the holographic aspect to work. When my student viewed his EOTech with his head upright, everything worked normally. But, when he turned his head while acquiring an awkward position, his glasses rotated enough to conflict with the polarization of the EOTech. The result was no light coming through the optic, and the shooter thus looking at a blank screen!
Never had that happen and I often shoot with an EOTech and sunglasses. Anyone else had that issue?
October 8th, 2008 at 9:16 am
I can’t say that I have, but then again, I only have iron sights. However, even if you own both an EOTech and sunglasses, two conditions must be met for the problem to appear: First and foremost, the sunglasses have to be polarized. Second, you must tilt your head. Miss either one of those and you will not have a problem.
October 8th, 2008 at 9:51 am
But are your sunglasses polarized?
October 8th, 2008 at 9:52 am
yes.
October 8th, 2008 at 9:59 am
I recall seeing this (or a similar story) on John Farnam’s site. It’s certainly possible. The whole point of polarization is to remove glare and reflection, which is what the reticle on a Eotech is, a reflection.
October 8th, 2008 at 10:15 am
You all sound like the philosophers who argued over how many teeth a horse had, and killed the kid who went outside and counted them.
Get the polarized glasses, fire up the optic and rotate the glasses through 180 degrees. My guess is when the polarizing bars crisscross, the image will dim a lot but not totally vanish.
October 8th, 2008 at 10:21 am
I own EOTechs and polarized lenses, so this interested me. I will certainly be testing this out.
My problem with polarized PLASTIC lenses (i.e. Oakleys, Wiley X’s) is that they distort vision, especially at the edges, and they distort color as well (look at your i-pod or laptop screen through plastic poliarized lenses).
I never had this problem with glass polarized lenses (i.e., Ray-Bans).
Wonder why the difference.
October 8th, 2008 at 10:24 am
Maybe some info on polarized materials is in order: First, most sunglasses worth more than $5 are made with polarizing lenses. When two polarizing filters (says, two sunglass lenses or a sunglass lens and an EOTECH sight) are in line, they can either transmit just about all the light, block just about all the light, or block a proportion of the light based on the angle of rotation between the two lenses.
So when a sunglass lens and a holographic sight are not lined up “just so,” there is a loss of light transmitted through them to the eye. Usually it is not enough to notice. If the alignment gets bad, the dot is lost as the sight dims. If it gets gets worse, the view is like looking through welder’s goggles (very very dim to black).
Can one position one’s head 90 degrees to the optic? Yes, under extremely odd shooting positions such as laying on one’s back firing to the side.
Knowing there can be a problem, the solution is to ditch the shades if one drops to the ground in a firefight, I would suppose.
October 8th, 2008 at 11:10 am
Polarized filters emit light in only one plane blocking all others. What happened was the shooter rotated the polarized plane of the sunglasses 90 degrees to the plane of the sight. Thus the light from the sight was blocked by the plane of the glasses since it was 90 degrees out of phase.
Whether this happens to any one individual depends on the plane orientations, whether the polarization is precise or covers a range of angle, etc.
As suggested try looking into your sight while rotating the glasses to find the angle in which the visual goes dark.
I have a pair of sunglasses that has a problem with the LCDs on gas pumps if I cock my head slightly right. Rotate left and I can read them with no problem.
October 8th, 2008 at 11:50 am
If you recall from Reno, I have an Eotech on my MKII, looking at it right now, with my decent polarized Ray Ban sunglasses, I can tell you the image in the scope is visible regardless of lens/site/head orientation.
Myth busted.
October 8th, 2008 at 11:51 am
That should be sight, not site.
October 8th, 2008 at 12:11 pm
Oy. I say get out the scope & shades, I’m ignored. JKB says do it and you jump.
If I had a tie I’d adjust it and say “no respect, no respect at all.”
October 8th, 2008 at 12:13 pm
I guess you missed the part where me and jimmyb said we’ve done that?
October 8th, 2008 at 12:41 pm
Lenses can have a circular polarization as well.
October 8th, 2008 at 12:46 pm
If they are both polarized lenses, then it will happen when they are out of phase. If you didn’t have it happen, either your shades aren’t polarized, or you never got them into perpendicular phases. (Or the shades are poorly polarized, and the effect is minimal.)
I’ve actually held two lab-grade polarized lenses and rotated them against each other. (Well, the rings. You don’t want to actually run the lenses together.) When they are perpendicular, it is opaque. Completely. A good tutorial is here:
http://www.laramyk.com/education/dispensing/polarized-lenses.html
October 8th, 2008 at 3:22 pm
I get an Unclelaunche and all I get is two measly comments. Heh.
October 8th, 2008 at 4:53 pm
I wrote about that here. I had that problem with an older Bushnell Holosight. Back then they weren’t addressing the issue, and this sight’s reticle was attenuated in the upright position. Now EOTechs all have their polar orientation set to allow full brightness when upright, using polarized glasses.
To say you get a “blank screen” is an exaggeration. I still use the old Bushnell with my polarized shooting glasses. I just have to crank up the brightness as far as it’ll go and it’s OK.
October 8th, 2008 at 5:53 pm
My fathers car has tinted windows that are polarized. He got a pair of cheap sunglasses and when he put them on he could barely see out the rear window. If you tilt your head 90 degrees and look out it was fine.
Also, not all red dot scopes will do this. In fact I bought a bushnell multi-retical red dot and it comes with polarized lenses you can take on and off to lessen the glare (the 2 lenses are housed in one rotatable housing, so when you attach it to the sight, one lens is stationary while the other one moves, which makes it brighter and darker).