The Ultimate Firearms Destination for the Gun Lifestyle

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The Ultimate Firearms Destination for the Gun Lifestyle

Home » Gear » The Holographic Sight Advantage of EOTech

Before we dig in, let’s address terminology: The term “Red Dot Sight” (RDS) is generally used as a catchall for red-dot sights as well as holographic weapon sights (HWS), whether they have red, green or gold, dots or reticles. Which, while accurate to a degree, is also confusing, because both types of sights utilize very different means of producing an aiming point. Where they look similar on the outside, a holographic sight is much more complicated on the inside.

A battery-powered red-dot sight produces its aiming point by beaming light from an LED onto curved or slanted glass coated with a reflective material, which reflects back as the aiming dot. Holographic weapon sights, such as EOTECH’s EXPS models, incorporate technology from the Heads Up Displays (HUD) found in fighter jets and helicopter gunships, and use a laser diode to project a hologram of a three-dimensional reticle that’s been recorded within a clear, flat, glass laminate.

Whether you’re dogfighting at 30,000 feet or gunfighting at 10 yards, speed matters. When you bring an RDS to your eye to engage a target downrange, your eye immediately focuses on the brightest point in your field of view, the aiming dot, because it’s closer to your eye than the target, and not on the same plane. You then have to make a conscious decision to take either a reticle-focused shot or a target-focused shot. But thanks to the magic of holography, a holographically projected reticle always appears as if it’s on the same plane as where your eye is focused, saving you time that would otherwise be spent deciding and then refocusing.

One advantage of a holographic sight is that the dot can be made very small. The target on the left represents a 4 MOA Red Dot Sight, and the Target on the right represents the 1 MOA center dot of an EOTech.

You’ve likely heard that field of view isn’t a factor if you shoot with both eyes open — but step off the square range and start engaging targets while you’re moving, shooting around obstacles, or from any other suboptimal position, and FOV starts to matter. Compared to an RDS with a lesser FOV, the Holographic Sight’s larger window—and its lack of a view-restricting enclosure tube — allows the eye to pick up the reticle earlier in the process of bringing the weapon online to the target.

EOTECH’s holographic reticle resolves sharper than the typical, somewhat blurry, 2-MOA or 4-MOA dot of an RDS, but the design itself is also more useful, with a 68-MOA outer circle that allows for lightning-fast aiming at close quarters as well as range estimation at distance, and a 1-MOA center dot for increased precision at longer ranges, with reticle options available that include additional 1-MOA dots for holdovers out to 600 yards. 

Another advantage of EOTECH’s reticle becomes apparent when using their optional magnifiers. When magnifying an RDS, the dot will maintain the same size relationship to the target as it would when not magnified, meaning the dot will increase in size along with the target. With a holographic reticle, the crispness of the dot is made more clear, as it is less affected by the distortion of a curved pane of glass. 

All optical sights are subject to some degree of parallax error, and due to their use of curved or slanted glass, conventional red-dot sights are no exception. Holographic sights are even less subject to parallax because all of the optical elements you look through are flat. 

If you’ve used an RDS, you’ve probably noticed a tint, a result of the dichroic coating used to reflect the light from the LED emitter (that produces the aiming dot) back to the eye. That coating also blocks some of the light being reflected back from the target scene, altering both the contrast and color of what you are looking at, which has a negative effect on both-eyes-open shooting, because one eye sees the target and surrounding area in normal color while the other eye sees it with a tint. The tint also reduces light transmission to some degree, which can impair target acquisition in low light conditions. 

A Holographic Sight, by contrast, does not rely on a reflective coating to produce its reticle, which is why you don’t see a tint, but do see “true contrast” with all the light transmission possible through clear, flat, glass.

EOTECH’s holographic weapon sights are extremely rugged, which is one of the reasons they were re-awarded SOCCOM’s contract for the Close Quarters Battle Sight. Higher-end red-dot sights are also very durable and can be found in service with various units, but what sets the Holographic Sight apart is again one of the benefits of holographic technology: In the unlikely event the front and/or rear window is shattered or partially obscured by mud or snow, the entire reticle will still be visible.

Unlike red-dot sights and lasers, the holographic reticle projects no forward light, and is visible only to the operator. The absence of reflective coatings also means that add-on filters are not needed to block reflections that could give away the operator’s position.

So why would anyone consider an RDS versus a Holographic Sight for a carbine/rifle application? In two words: “Battery Life.” The laser diode used to create the HWS’ magic reticle requires significantly more power than the LED in an RDS. So while EOTECH models offer as much as 2,000 hours of continuous runtime (as well as Auto-Shutoff and Low-Battery Indicator features) an RDS can provide many times that. So you have to ask yourself, are you the type of person who can set a calendar alarm to remind yourself to change batteries once a year, or the kind who can only set a calendar alarm to change batteries every five years? That’s a rhetorical question, in case you missed it. 

EOTechs Available at Optics Planet

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