High-Tech Sights

Reflex Sights
Technically speaking, the term reflex sight refers to any optical sight that reflects a reticle image (or images) onto a combining glass for superimposition on the target. So any of these dot sight are technically reflex sights. In practice, however, the reflex sight terminology has come to describe such sights that are not battery-powered, and thus differentiated from electronic dot sights. Illumination in reflex sights is provided by ambient light, an internal passive illumination material such as Tritium, or can be fed by a fiber-optic light gatherer, or by a combination of both.

Similar to electronic sights, reflex sights use refractive or reflective optical collimator to generate an image of a luminous or reflective reticle, which is reflected off a dichroic mirror or beam splitter to allow the viewer to see the field of view and a reflection of the projected reticle. If no magnification is utilized, this gives the viewer a theoretically parallax-free image of the reticle, superimposed over the field of view at infinity.

The current leader in reflex sight technology is Trijicon, whose newly introduced Ruggedized Miniature Reflex (RMR) is about half the size of a pack of lifesavers, durable under the most extreme conditions, fully adjustable for windage and elevation, and available either with or without an integrated fiber-optic light feed for maximum brightness even under the dimmest light conditions. Trijicon uses this same technology to illuminate the reticle in its AccuPoint line of conventional hunting scopes. I've fallen in love with this little gem with it's integrated Weaver-type mount attachment for use on handguns, shotguns and medium-range hunting rifles alike.

Holographic Sights
Battery-powered holographic sights, invented and pioneered by EOTech as the Holographic Weapon Sight (HWS) and subsequently adopted by Bushnell in its popular HoloSight, are the most technically advanced of all present new-generation optical hunting sights. The technology is admittedly complex. Holography is described scientifically as a wavefront reconstruction process. Unlike a camera, which forms and records a two-dimensional image of an object on film, a hologram records and then reconstructs the light field propagating from a three-dimensional object. EOTech says that a good analogy is the recording and playback of sound, wherein sound waves are encoded and recorded on a disk. With proper decoding, the original sound waves are reconstructed.

In holography, the light field is encoded in the form of an interference pattern and recorded as refractive index variations on a clear window. The decoding is achieved by illuminating the hologram with laser light, and the light field propagating from the object to the hologram window is reconstructed. Thus, a viewer cannot tell if the three-dimensional image he sees is live or a holographic reconstruction. The laser beam, incidentally, is by necessity very low-level, contained completely within the sight unit and not reflected back into the user's eye. It merely serves to create the holographic image of the reticle that the shooter perceives.