Holographic sights. Red dots. Reflex sights. These terms get tossed around a lot—often interchangeably.
After all, how different could they be? Each of them features a reticle, a glass surface, and 1x magnification, right?
The truth is that red dots and holographic weapon sights work on two completely different principles. Here’s the CliffsNotes version: red dots use an LED emitter to project a reticle onto glass. Holographic sights use a laser diode and mirrors to “project” a reticle that appears to be floating on your target. Of course, there’s more to it than that, but it’s a good place to start.
As stated, red dot sight uses an LED emitter to project a reticle onto glass, which is then bounced back to your eye. The LED emitter uses very little battery power, so red dots can have battery life up to 50,000 hours. And because the design is so simple, red dots are much lighter and more compact than holographic sights.
There are two types of red dots: tube red dots (see the image above), and reflex sights.
Tube red dots feature enclosed optics that are protected from the elements. Field-of-view is limited, but the optics are shielded from outside factors.
Reflex sights are far more common than tube red dots (and what most people are referring to when they use the term “red dot.”) Reflex sights provide a much wider field-of-view, but the optics are not protected from the elements, and if something blocks the light path, they don’t function properly. That said, they’re easily “scaled down” for use on pistols and SBRs, so if you want a compact optic, a reflex sight is probably your best bet.
Holographic sights use a laser diode and mirrors to project a holographic reticle that appears to be “floating” on your target. Red dot sights require your eye to move back and forth between the optical plane and the target plane, but holo-sights allow you to focus on both the target AND reticle at the same time. This makes them much less susceptible to parallax distortion. Most operators prefer holographic sights for exactly this reason.
They also offer another significant advantage over red dots: even when the sight window is partially shattered or obscured by snow or mud, a holo-sight will keep on functioning. One of the many reasons they’re trusted by America’s elite in the most extreme, hostile environments in the world.
THE PROS & CONS
Red Dot Pros:
- Very simple design
- Lightweight and compact
- An entry-level red dot is far more affordable than the cheapest holographic sight
- Simple design leads to very long battery life
Red Dot Cons:
- Will not function if the lens is broken or obscured
- Forces your eye to move back and forth between optical plane and target
- Subject to parallax distortion
Holographic Sight Pros:
- Projects the reticle directly onto your target, allowing you to focus on the target and reticle at the same time
- Significantly less parallax distortion. No matter where in the glass the dot appears, if you put the reticle on the target, you will hit the target.
- Faster in close-quarters scenarios
- Works better with a magnifier than a red dot
- Can still operate with the front lens broken or obscured by snow/mud
Holographic Sight Cons:
- More complicated design means they’re heavier and bulkier than red dots
- …and subsequently more expensive too.
- Laser diode requires more battery power than an LED emitter, so battery life is shorter.
- Generally too big for pistols
So there you have it. We hope this article helps you decide which optic is the right choice for your firearm. If you have any questions, leave ’em below and we’ll do our best to answer.
Thanks for reading!