Newer thermal units produce very good images. Jim Shepherd photo.

Great advances have been made in optics, including conventional, reflex, holographic, night vision and thermal imagers. The question is when does the gear outrun the use?

It should suffice to say that various vision enhancement devices each have a place. It’s like anything else; proper use is critical. That takes thought and preparation. We’re not always good at that.

I’ve done the deep dive on the “see in the dark” optics as it relates to personal defense. In my meanderings, I’ve found some very smart takes on the new gear.

First, night vision refers to devices that amplify ambient light allowing one to “see” what – or who – is out there in the dark. It can be weapon mounted, helmet mounted and hand-held.

Thermal uses the wavelength outside the visual spectrum identifying variation in temperature. Seeing the intruder’s body heat, for example, cues you to his presence. If he’s without darkness vision enhancement, I read, and you have it, you can watch him from the shadows.

An advantage.

You may detect a heat signature from a considerable distance, if that makes a difference in personal protection. Night vision units, particularly commercially available gear, may be limited in terms of distance. For personal protection use, this shouldn’t be an issue.

In the rain, fog or smoke – or in light vegetation – thermal rules.

I’ve seen some sources claim that positive visual identification is quite possible – and superior – with night vision gear than is possible with thermal. Just because someone is somewhere they shouldn’t be doesn’t mean you can use deadly physical force. If the vision enhancement optic – NV or thermal – is weapon-mounted, you are facing some moral (and potentially legal) issues.

Consider the same issue with weapon-mounted lights – or magnified optics on a centerfire hunting rifle. If you’re “searching” (or “glassing” the area looking for game), you’re muzzling everything you see. That’s a serious Rule 2 problem. You’re using the optic as an optic when it’s really a gun.

How about threat identification? At distance, decent thermal optics can help you differentiate between a feral hog and a deer.

For home defense, imagine having to gear up with helmet-mounted night vision (did you keep the battery in the unit?) on top of everything else you have to sort out when half-asleep – and even then, do you have enough visual acuity to ensure you’re not seeing a family member?

Regardless, if the other side turns on a light, we’re having to jettison gear. And why didn’t you turn on a light to start with?

Or call out to see if they’d say who is there?

When I asked someone who had a record with both search and rescue and dope eradication missions in Southern California, he replied, essentially, as follows:

“Our SWAT folks … have weapon mounted lights on everything, so there is not much need for NVG. However, our helicopter pilots have some form of NVG -- allegedly so they can fly at night, but frankly, I don't recall them ever doing it. They always defer to the fire department helicopters that use NVG all the time. NVG is not needed for urban helicopter patrol at night, just up in the mountains or more rural desert areas with no ground lights. Should there be a need for a rescue, etc., they always turn it over to the fire department if it is after hours of daylight. One of my collateral duties was running the eradication team where we used aerial surveillance to locate the weed grows in the national forests. Once a grow was located, members on the team would go in at daybreak, arrest any of the gardeners if they were present, and pull all the plants and airlift them out. So, to answer your question, I don't see a use in everyday police work for IR or NVG. There are some special occasions, but few and far between these days.”

For hunting, thermal has become quite the hot ticket. Night vision likewise has application for some law enforcement operations. If you have acreage and find a need for their use outdoors, the new technology is the way to go. Just remember to positively identify a target – and, please, don’t search with a gun-mounted optic.

— Rich Grassi