Jul 162017

As a general disclaimer, I have more or less stopped reading optics articles in various gun magazines since they run the gamut from ignorant to fraudulent and virtually all are fluff pieces for whoever spends the most on advertising at any given time.  Every once in a while you stumble onto something accurate, but that is a rarity.  What irritates me the most is that most of what you need to know to write about sporting optics coherently is not that complicated and can be learned with minimal effort.  Yet, if there is a gunwriter out there writing about optics who put in that effort, I am not aware of him.  Even internet bloggers who face a fair amount of competition and, you would think, should pay more attentions, seem to choose technical illiteracy as life goal.  I remember running into a website called OpticsDen or something along those lines a little while back.  I have all the admiration in the world for the guy’s hubris, but enthusiasm is a poor substitution for competence.

This time around, I stumbled onto an article by Petersen Hunting that is linked from SWFA Outdoors blog.  SWFA are good people, so I usually read through whatever they post and that is how I ended up on the Petersen Hunting fluff piece on the new Trijicon IR Hunter thermal riflescope.

This particular article was written by a gentleman named Keith Wood.  I have never met him and have no idea of what his background is.  It is not my intention to call him out, but the only mistakes that were not made in his article are spelling  and punctuation.

I am going to go ahead and assume that neither he nor his editor has ever seen a thermal scope before since he writes about how shocked he was by the compactness of the IR Hunter.  Virtually all of the thermal riflescopes of similar resolution and FOV from different manufacturers use more or less the same optics and image sensors, so they are all about the same size.  They are some variations due to packaging differences.

Then he compares their weight to traditional long range riflescopes.  I am not sure why since they do not compete against each other and do largely different things.

Then it turns out that he does not understand the difference between zoom and magnification (that should pretty much preclude him from writing about optics, but then again, if this was the criteria, the number of gun writers who talk about optics would go down exponentially).  In a nutshell, magnification is how much closer the object will appear through an optic than it does with your naked eye.  Technically, it is the ratio between the FOV going into the optic and FOV going out of the optic when talking about afocal telescopes which riflescopes are.  Zoom, is how broad a range of magnifications an optic supports.  For example, in a 3-9×42 riflescope, the range of magnifications is from 3x to 9x and the zoom ratio is three (9x divded by 3x).  In fixed power 6×42 riflescope, the magnification is 6x and there is no zoom, since it is a fixed pwoer scope.  Magnification does not change.

IR Hunter thermal sights, like virtually all commercially available thermal sights, are fixed power designs.  Their magnification range from 1.5x for the 20mm lens to 4.5x for the 60mm lens (the longer the focal length of the lens, the more magnification).  There is no optical zoom.

Technically, there is a digital zoom, but that is up for a discussion as well, since in thermal riflescope, digital zoom simply magnifies the center of the image, but does not actually give you any more detail: everything looks bigger, but blurrier.  Still, the article again confuses zoom with magnification and misrepresents Trijicon’s specifications.

Then there is the rest of the article where Trijicons marketing is badly re-hashed, like the “special edge detect targeting mode”.  I am not sure what is so special about it, since I distinctly remember it being incorporated into one of the first ENVG systems I used to work on at Raytheon about 15 years ago.  All thermal sight manufacturers have the capability of incorporating it; some do and some do not.  There is no magic pixie dust involved in that.  Oh, and, apparently, a basic MilDot reticle again qualifies as a “advanced design”.  It does, if you have been living under a rock and missed the last twenty years of the evolution of precision shooting.

Last point: Trijicon did not develop this product line.  It was developed by a company called IR Defense and Trijicon inherited the product line when they bought the company.  To the best of my knowledge, the only contribution Trijicon made to these products, was added a Trijicon label and raising the price.

OK.  Rant OFF.

Before I wrap up: while this article for some reason irritated me, the product itself is good.  I looked a bit at the IR Hunter in the past and thought it was the best user interface of all the thermal sights out there and if I were in the market for one, it would be at the top of the list.  As far as actual imaging performance goes, for the same image sensor resolution and FOV, there is virtually no practical difference between thermal sight from different makers.

IR Hunter uses microbolometer cores from BAE (or at least they used to).  FLIR uses their own.  Most quality thermal sight makers use BAE, FLIR, DRS, Raytheon or Sofradir with the first two being most common.  There is little practical performance difference between them.  There is a Chinese microbolometer core maker out there that pops up now and then, and their stuff is a bit worse, so thermal sights with those cores are not quite as good, but they are not quite as common either.

If you are selecting between different thermal sights from quality makers, you should be, essentially, making a decision based on the user interface and some of the features.  In that regard, IR Hunter is worth a look.



 Posted by at 11:35 pm

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