Let's get the important thing out of the way right now: I've had one of these for over 20 years and yes, it works just fine. Open it up and the needle will find mag north. But so will any $0.25 button compass. One thing I've learned over time is that a compass needs to give you reliable information beyond just pointing to mag north, and the Cammenga falls short, especially compared to mirror compasses, mainly because of in-built error. And yes, I do know how to use a lensatic properly.
Fanboys will go on and on about how the aluminum alloy construction make this so rugged, but Cammenga clearly states that the compass is rated to withstand a drop of three feet onto sand. Any baseplate or mirror compass will withstand the same thing. Another thing Cammenga fans will talk about how this isn't liquid filled so there's no chance of bubbles. But the truth is bubbles are rare. I have a 45 year old Suunto and a 30+ year old Silva, neither of which have bubbles. And even if one does get a bubble one can get another liquid compass and still have spent less on those two than on one Cammenga.
But all of that really no different than arguing about Xbox vs Playstation. The real test is how the Cammenga compass performs in real life compared to a mirror. The answer is fine, just not as well as mirror compasses for anything other than calling in an airstrike or for nighttime orienteering.
Let's start with some summaries:
The good:
* durable construction using aluminum alloy for the housing
* the compass is very dependable, and will work consistently time after time
* remains effective in extreme temperatures
* tritium is self-illuminating, bright, and very easy to see in low light or darkness
* offers both azimuth (degrees) and mils (radians) to get bearings
The bad:
* it's heavy, weighing 9oz (compared to 3oz or less for mirror and baseplate)
* it's cumbersome
* the needle can be jittery and over-reacts to the slightest move of your hand
* reading an azimuth means fiddling with the lens housing to get the proper angle/distance to read the degrees/mils clearly
* no built-in declination adjustment
* holding the compass properly to get a reading (up to the cheek) can be awkward
The ugly:
* aging eyes or glasses makes it almost impossible to get a clear view of a distant landmark then shift to reading azimuth/mils
* degrees are marked in increments of 5 meaning you're often guessing at azimuth
* the solid, opaque housing means you need a separate protractor when using a map
* the needle card does get stuck now and then so you have to shake the compass to re-set it on its pivot
* $100 is just too damn much for a compass with this much error
When compared to a mirror compass in the field one finds that shooting an azimuth with a mirror is faster, it's easier to use with a map, and more accurate because of the 5 degree markings on the Cammenga where mirror compasses (like my Silva) use 2 degree markings. This means error is built-in to the Cammenga and unavoidable. Also, one reads the azimuth directly off the card rather than by setting a bezel to put the 'red in the shed' with mirrors. In theory that should give one higher precision because there's less worry about parallax error, but in practice that 5 degree marking and a shaky needle adds more error. Finally, after setting the bezel on mirror compasses you can easily break out the map and do what you need to. Not so with the Cammenga.
One can argue that mils are much more accurate than degrees can ever be, and you'd be correct. Except, other than the military, who uses mils when hiking or camping? Nobody, that's who. It's *always* in degrees. Unless, of course, you're playing army with your friends.
Now, none of this is to say that the Cammenga is a bad compass. Far from it. I've had one for 20+ years, long enough so the tritium is now worn out, and I do still take it with me when camping or hiking because I always carry a second compass as a backup just in case. But I almost never use the Cammenga any longer because in my experience, there simply is no real-world advantage over a mirror (unless you need to direct mortar fire) - especially at a $100 price point.
The only real advantage the Cammenga has is that it's perfect for the weekend warrior with the military fetish who needs an official army guy compass to go with the tactical socks, assault sunglasses, and molle fanny pack, to complete the survivalist prepper costume needed to cosplay commando and call out direction in mils because, hey, everyone wants to pretend to be Rambo now and then.
