Serious outdoor enthusiasts are divided on the question of whether to pack a lensatic or baseplate compass. Here’s a quick rundown of the differences between these two types of compasses in terms of ease of use, precision, and packability to help you take sides.
The Difference Between a Lensatic and Baseplate Compass
A baseplate, or protractor compass, has a clear, plastic base that can be used as a protractor on a topographic map, and a magnetic needle that swings in a capsule filled with fluid to dampen quick movements of the needle. The most accurate models have a folding mirror that allows the user to read the compass (reflected in the mirror) while sighting distant objects.
A lensatic compass uses a lens to allow the user to read the compass bearing with just a quick downward glance while sighting. These compasses generally use a magnetic disk rather than a needle, and dampening with either fluid or, in the best models, electromagnetic induction.
Ease of Use
Both types of compass require a little study and practice, and neither have a clear advantage in ease of use. The lensatic compass may have a slight advantage in initial comprehension for beginners because the direction seen through the lens is always the way you are facing. With a baseplate compass, the dial (bezel) has to be set before the bearing can be read. A disadvantage of the lensatic is the lack of a magnetic declination adjustment—this correction has to be done mentally, which is not a big deal, but introduces an additional opportunity to make a mistake.
Used properly, both types of compass can produce reasonably precise readings, but the lensatic compass has a slight edge. The narrow, magnified field of view seen through the lens, with just a glance down to read the direction, is a powerful combination. However, for most outdoor recreational activities like backpacking and hunting, a degree or so extra precision probably isn’t going to be the deciding factor.
Weight and bulk are factors to consider, especially if you do long-distance backpacking, lightweight expeditions, or any other activity where every ounce makes a difference. High-quality mirrored baseplate compasses weigh less than 3 ounces and have a slim profile of just over a half inch. The rugged, aluminum Cammenga Model 27 is twice the thickness and twice the weight, but it is very durable, and has no liquid, so leaks are not an issue.
All three of these companies make good handheld compasses for land navigation and all three also make some low end compasses that I would not recommend. At the top end, it is difficult to say which company builds the compass that will perform the best or last the longest, so I would focus on the getting your favorite features for the best price rather than reputation because just who is making the compass that you are inspecting not as straightforward as you might expect.
In 1932 Silva became the first manufacturer of the baseplate (orienteering) compass, and built a reputation for quality around its Silva Ranger and other models. However, in 1985 , Johnson Worldwide Associates (now Johnson Outdoors Inc.) bought the North American side of the Silva company, and as of the late 1990s, compasses like the Ranger are no longer manufactured by Silva. Over the past few years I have seen an increasing number of negative reviews of the Silva Ranger, so there is some question about quality control since the transition to Johnson Outdoors. However, there is also an indication that Suunto compasses manufactures compasses for Johnson Outdoors, so I am not sure I believe in any huge discrepancy between the quality of these two brands. I have used both for many years.
The original parent company of the Silva Ranger is now called Silva Sweden AB and it still sells compasses under the Silva name outside the U.S., but get this, it has owned Brunton since 1996. So the Brunton Model 15 sold in the U.S. could be considered a more direct descendent of the Silva Ranger than the Silva Ranger that Johnson Outdoors produces. To make matters more confusing, some of the original Brunton-designed compasses are sold under the Silva brand name outside the U.S.
Suunto brand compasses were not involved in the acquisitions and legal dealings that produced today’s complicated brand identification, but the company apparently manufactures some compasses for Johnson Outdoors to be sold under the Silva name in North America.
The Brunton Model 15 TDCL is manufactured by Silva Sweden AB, the original manufacturer of the Silva Ranger (see Silva, Suunto, or Brunton? for details on this confusing branding issue). Like its competitors, the Silva 515CL and the Suunto MC-2D, the Brunton 15TDCL is a mirror compass with adjustable declination and clinometer, luminous points, rubber feet, and 1:24,000, 1:25,000, and 1:50,000 scales. The Brunton 15TDCLQ is the quadrant version.
Perhaps the most intriguing feature of this compass is the red bezel (compass dial). Whether the color enhances performance is debatable, but it sure looks cool. Another interesting feature is the rounded corners giving the compass a sleek look and making it just a little easier to slip it out of a cargo pocket, but the rounded corners don’t do anything to reduce the weight which is 3 ounces (compared with 2.65 for the Suunto MC-2D and 2.2 for the Silva Ranger 515CL).
The features of this compass are competitive, but three additional benefits really make the Brunton 15TDCL stand out—it’s price is as good or better than comparable brands, it is made by Silva Sweden AB, the original, highly respected manufacturer of the Silva Ranger, and it comes with a lifetime warranty. Hard to beat!
The Silva Ranger 515 CL is one of the most popular handheld baseplate (orienteering) compasses on the planet. It has been my compass of choice over a 20 year career as a park ranger and forester. I have had one of my Silva Rangers for 15 years. I have broken or lost others.
This compass has a bright, easy to read bezel (compass dial), adjustable declination, a cool sighting slit in the mirror, a clinometer and all the right map scales. It’s also the lightest compass in it’s class, weighing in at 2.2 ounces (compared with 2.65 for the Suunto MC-2D and 3.0 oz for the Brunton 15TDCL).
Unfortunately, the reliability of the trusted Silva brand is not enough for me to recommend that you buy this compass without even looking at the competition. In 1998 Silva’s U.S. operations changed hands (see Silva, Suunto, or Brunton?) and there have been some concerns expressed about a slip in quality. I have purchased two of these models in the past few years, and I had some POTENTIALLY quality-related issues with both of them.
One, I bought in about 2003 and I noticed the bezel (compass dial) felt a little loose. I have seen other reviews that mention this issue. However, the play in the dial felt much larger than it really is. I’m a forester, not a surveyor, so the 1/10th of a degree of accuracy that I might be loosing with the loose dial is a non-issue. Local magnetic anomalies are a much larger concern than a little play in the bezel anyway. The real question is whether it is indicative of some greater lapse in quality. So far this does not seem to be the case and I still use the 515 CL each summer in the field and it works great.
A more recent experience with this model came in 2009 when I purchased a Silva Ranger 515CL for a Map and Compass video I was creating. Within a week the compass developed a huge bubble, and within a month all the liquid had leaked out. On the surface this seems like an indication of poor quality, but I have no evidence that the rate of leaky compass production is any greater with this model or brand than with its competitors. I have bought at least 30 of the pre-1998 Silva Rangers when I managed equipment for my fellow park rangers, and a couple of those developed leaks too, but I also had a Suunto compass with a leak a few years ago. So I am not ready to make any accusations about quality based on my experiences with the new Silva Ranger.
My recommendation is to check out the prices of competitive models and, if you like it and get a good deal on it, give the Silva Ranger 515CL a try. If you have lingering doubts, get your hands on one at an outdoor store before buying sight unseen.
Making a compass to demonstrate the concept of magnetism is easy. Simply magnetize the point of a sewing needle by rubbing it on a magnet–try to do this in just one direction. Then float the needle in a bowl of water. If the surface tension of the water is not sufficient to keep the needle afloat, use a small piece of cork to float the needle.