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Discussion Starter #1
I just got my eotech 512 today and im concerned there is something wrong with it. Upon first bringing it in and looking through the sight it was fogged (it was about 35-40 outside and 70 inside). The fog went away after a few minutes, but i was under the impression that this was nitrogen filled to avoid fogging? This is (or was) a military grade sight, i cant imagine them being in the freezing cold and busting into an enemies 70 degree house and not having their sight work...so i dont think this is right.

The second issue is parallax, i was also under the impression that this is supposed to have almost no parallax. I watched videos where they showed moving the camera side to side and the dot barely moved. Well on mine, i put the gun still on the table and look through the sight, move side to side and the dot moves many inches from point of aim, even looking just a few yards away.

I bought this brand new from sportsmansguide.

Thank you
 

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What would be filled with nitrogen? Its just a glass lens that a holographic image is shown on.
It's no different than if you were inside a walk in freezer wearing glasses, and then walked out into a 70* room. The glasses will fog up.

As far as parallax, read this-
Non-magnifying reflector or "reflex" sights have the ability to be theoretically "parallax free." But since these sights use parallel collimated light this is only true when the target is at infinity. At finite distances eye movement perpendicular to the device will cause parallax movement in the reticle image in exact relationship to eye position in the cylindrical column of light created by the collimating optics.[32][33] Firearm sights, such as some red dot sights, try to correct for this via not focusing the reticle at infinity, but instead at some finite distance, a designed target range where the reticle will show very little movement due to parallax.[32] Some manufactures market reflector sight models they call "parallax free,"[34] but this refers to an optical system that compensates for off axis spherical aberration, an optical error induced by the spherical mirror used in the sight that can cause the reticle position to diverge off the sight's optical axis with change in eye position.[35][36]
 

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Discussion Starter #3
It says:
"Waterproof, fogproof construction"
"Nitrogen-purged optical cavity"

I wear glasses with a coating, and they didnt even fog up when i walked in.

Then why has every review i read and watched say that parallax is nearly non existant on this holographic eotech? In videos ive seen multiple optics (such as the aimpoint and this eotech) tested side by side, and this one had far less movement of the dot as the camera was moved around.

Both of these were some of the strong reasons i chose this far more expensive holo over some of the cheaper medium end red dots.
 

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Discussion Starter #4
I was thinking, is it possible that this effect of bad parallax (when others dont have this problem, i have read many places and people say the dot stays in place) is because i wear glasses, and maybe those others that dont have problems dont? Still, that doesnt make much sense to me, for it to be this bad. Plus, many wear glasses.
 

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Call Eotech tech support and check to make sure you have an Eotech and not a counterfeit. I don't know where you bought it but there are counterfeits out there.
 

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Posts were from 2016. Just a stab in the dark, the sportsman's guide got their hands on a faulty product from the past to sell for a healthy profit.

My past experiences with s.g. has made me very wary of spending my money with them, which I haven't for many years.
Ok, thanks for the update..
 

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Discussion Starter #9
Interesting that sportsmans guide may be selling old faulty optics. I was going to call them for a replacement, but maybe i'll try contacting the manufacturer instead, and hopefully get a functional replacement.

I do have to say though that my experience with sportsmans guide has been terrible. I had all sorts of pains with them. Its unfortunate though because they are recommended by a lot of well known youtubers.
 

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Thoro,

Just a thought, I do not do any business with anyone that I have had trouble with. I might give them one chance because Murphy is alive and well and things can go wrong with any company. But after that SEEYA!;)
But is the 512 Fogging up on the inside or the outside of the Lens.
If it is fogging on the inside of the Unit. Call EOTech, their customer service has in the past years has always been exceptional. I have several and never had an issue. If fogging on the outside like a camera lens one can not do that much about it when they are instantly exposed to one extreme and then the other. If I am going to do that even with a good quality rifle scope or camera. I always keep a lens cloth or piece of cotton cloth like T-Shirt material to wipe the lenses off for a few minutes.

03
 

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The lens tube is purged with nitrogen to remove any moisture, that way it wont fog from the inside.
If it is fogging on the inside it has a bad seal.
 

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I just got my eotech 512 today and im concerned there is something wrong with it. Upon first bringing it in and looking through the sight it was fogged (it was about 35-40 outside and 70 inside). The fog went away after a few minutes, but i was under the impression that this was nitrogen filled to avoid fogging? This is (or was) a military grade sight, i cant imagine them being in the freezing cold and busting into an enemies 70 degree house and not having their sight work...so i dont think this is right.

The second issue is parallax, i was also under the impression that this is supposed to have almost no parallax. I watched videos where they showed moving the camera side to side and the dot barely moved. Well on mine, i put the gun still on the table and look through the sight, move side to side and the dot moves many inches from point of aim, even looking just a few yards away.

I bought this brand new from sportsmansguide.

Thank you
Yes
Never buy premium products from Sportsmans Guide
 

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Discussion Starter #15
Concerning parallax, there is no such thing as a parallax free reflex/red dot/holo sight. Some are better at mitigating it, but all have parallax.

Here's a link that describes it nicely (unfortunately the links to the included videos do not work).

https://www.thefirearmblog.com/blog/2016/07/26/no-such-thing-as-parallax-free/


HydroR every video i've watched and every guide of read says that holographic sites (as compared to regular red dot) have extremely minimal parallax. I've watched videos where they move the camera far side to side and up and down and there is only the slightest amount of movement from original point of aim, with mine the dot moves with every slight movement of my head, it looks nothing at all like the videos. Low parallax is one of the main reasons i chose a more expensive holographic, without that it doesnt seem much better than a cheaper plain red dot.
 

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Holosights are not inherently more parallax free than a red-dot or a reflex. The only thing that differentiates them is the how the reticle is generated and projected onto the lens. As noted in the article, what matters is where the reticle is focused in terms of distance and any mitigating methods the manufacturer uses (such as a Mangin mirror). Sights with smaller view lenses have less apparent parallax as well because you can only move your eye so far off center compared those with larger view sizes. Most are set to infinity and in that sense, there will always be parallax at closer ranges. You probably noticed too that it's at its worst near the very edges of the lens.

I've looked at EOTechs, and personally for me, I do not like the laser generated reticle, it's grainy and has a bit of a "dazzling" effect. I find that distracting. I didn't notice that it had any more or less parallax than any other good reflex sight. Of all the ones Ive looked through (many) most of the better quality ones had similar parallax. The really cheap ones have the worst parallax.

Reflex, or "reflector" sights were actually invented in 1900. They were even used in WWI on aircraft and saw wide spread use on larger guns that needed to have fast target acquisition on moving targets, such as AAA. Powering them was a limiting factor for placement on handheld firearms, but that came about pretty quickly.

Realistically, you have to consider the intended purpose for this type of sight. It's definitely not designed for precision long range shooting, although modern versions can be employed effectively out to a few hundred yards if you take your time and line everything up. Even then, it's more an exercise of just putting a bullet into a man or animal sized target than shooting tight groups. These sights are best suited for "fast action" shooting at closer distances (CQB). Get the reticle on the target quickly and hit the bang button. Yeah, there's some parallax, but realistically it shouldn't be extreme enough to cause a miss at close range. You might not nail the target absolute dead center mass, the hit might be off a couple inches, but so what.

That not withstanding, it is possible there might be something wrong with yours. I know EOTech had some issues that had to be fixed, but since I'm not interested in their product, I haven't really followed along with the details of that.
 

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Discussion Starter #17
Yes its for home defense. Plus i'm also cross eye dominant (right handed, left eye dominant) and i understand that with holo i can keep both eyes open, where with regular red dot i have to close an eye (and use my weak eye, or switch hands which is even more awkward) correct?
 

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I am also cross eye dominate the same as you. I use a reflex sight with both eyes open without issue. It does take practice, even for folks that shoot the same side as their dominant eye, but you do HAVE to practice this and it does take a little time to get proficient at it. That is not true concerning non-holo sights at all, you can use a non-holo exactly the same. Again, from the gunner's perspective, they operate the same.

Let's make a small clarification, the term "red-dot" is often used as a general term across all of these types of sights. Holo is also used generically when referring to any type of red-dot sight. However, generally speaking, "red-dot", "reflex" and "holo" sights are three different types of sights.

When someone says to me "red-dot", I immediately think of a tubular style sight that uses just a single red-dot. These were the style of the early ones that saw use in IPSC shooting and other "fast action" type shooting events. Reflex sights came along later and even though it operates exactly the same, are the type that have the larger, rectangular lens and often include switchable reticle styles and sometimes colors. Holo sights, as you already know generate the reticle through a different means, but they operate from the gunner's perspective exactly the same as a reflex sight.

While a "red-dot" sight is typically quicker than iron sights, they aren't as quick as a reflex style simply because the viewing area is usually smaller so it takes a little longer to get your eye lined up inside the viewing area. However, there are some red-dot sights that have decent diameters to them.

So, to summarize, red-dot and reflex operate exactly the same in terms of how the reticle is generated and reflected to the shooter's eye. An LED mounted toward the rear shines forward onto the lens in front of it, and coatings on the lens reflect that light back to the shooter's eye. The only difference is the shape and style of the lens and the body of the sight. Holo sights generate the reticle with an actual laser and the reticle is projected onto the inside, or front side of the lens from the holographic grating. Other than that, they are used exactly the same way.
 

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Discussion Starter #19 (Edited)
I wont have an opportunity to practice too much unfortunately. Do you think the holo is still the best in that case, for quick acquisition and minimal practice home defense? I have a little less than a couple more months that i can return this to sportsmansguide. If i can get something cheaper than $430 that i spent on this, and have it work just as well, then that would be good (i would also prefer green, but its not super important, but having the dot inside the circle is important for easy acquisition, and a good FOV).

What do you use on your AR?

Thanks
 

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Look at Holosun. They have the tube and window style with a circle dot.
My AR's are carrying magnified optics. One has a 1-6x20 and the other has a 3x prism.
My Mini 14 and 30 are carrying Holosun tube type with circle dots.
 
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