“What’s the best rifle scope to buy?” “Are the European made Swarovski and Zeiss brands really worth the money?” With so many options available along with some fancy marketing jargon, the choice of “which scope is best for me” can be mind boggling. However, with some basic optics knowledge you can narrow the field pretty quickly.

Rather than jump right into the topic by talking about the virtues of a 40 mm versus a 50 mm objective lens or whether Nikon is better than Leupold, let’s look at the fundamentals of what makes rifle scopes work well.  

The basic function of a scope, whether on a rifle, shotgun, air gun or cross bow is to provide a crisp, clear view of the target with single and accurate aiming point. Although it sounds simple, it’s a relatively complex task that is made up of multiple components to include the mounting system, magnification range and, of course, the quality of the optics or “glass.” As with most complicated systems, there are just a few key factors that you really need to pay attention to and the other “bells and whistles” become a matter of preference. When it comes to scopes, these key factors are light transmission and parallax.

But before we get to light transmission and parallax, I want to put the “proof” thing to bed.  Some advertising campaigns focus on how their scopes are waterproof, fogproof and shockproof. Scope manufacturing processes have come a long way since the 50’s and 60’s and it’s extremely rare to find a new scope that has fogged up internally or has a broken cross hair. Even the cheapest of scopes have the “proof” characteristics mastered these days. Don’t waste your time worrying if your new scope will be “proof;” because it probably is. Just beware of scopes that are water, fog and shock “resistant.” Like a fine whiskey, they do need to have the “proof.”

When we look at an object, we are actually seeing beams of light bouncing off the object back to our eyes, so maximum light transmission is the most important element of a scope. In order to maximize clarity of the target, we need to see all the “light” it has to offer. While a scope transmits available light to your eye it unfortunately loses some in the process. Being highly polished, in addition to transmitting light, a glass lens will also reflect some of it away similar to a mirror. And the more that is reflected away, the less you can see through the scope. This loss can be minimized when the lenses are coated with a microscopic layer of refractive material, such as magnesium fluoride. Several thin layers can be applied for increased clarity and transmission. Coatings dramatically enhance light transmission and deliver more light the shooter’s eye.   

In the optics industry, coating designations include:  Coated — A single layer usually on one len’s surface; Multi-Coated — Multiple layers usually on one len’s surface; Fully Coated — A single layer on all lens’ surfaces and Fully Multi-Coated — Multiple layers on all lens’ surfaces. The number of coatings contributes significantly to the price and generally speaking the lowest priced scopes will simply be “coated” while the highest will be “fully multi-coated.” You should look for a scope that has fully multi-coated or at least fully coated lenses. This narrows the field considerably by screening away the coated and multi-coated options. Scopes with fully multi-coated lenses don’t have to cost a lot and are available from quality manufacturers starting around $100. I would much rather pay $100 for a scope with fully multi-coated lenses than pay $100 for one that is only multi-coated but with fancy turrets or endorsed by some outdoor celebrity.  I like to pay for what’s important to the task at hand and fully multi-coated lenses deliver the most crisp, clear view available.

Price is important to all of us and unfortunately most of us can’t always buy the best of the best. Are the top euro brands worth the money? Sure they are, but they’re quite often out of reach for most of us. Notwithstanding the “bells and whistles” the major cost of a scope is the quality of the lenses and coatings. So, when selecting a new scope I look for fully or fully multi-coated lenses and then work my way up the hierarchy of lens quality based on application. For plinking with the .22 in the back yard, a fully coated economy brand is more than acceptable. However, my primary deer rifle wears a fully multi-coated scope in the $100 neighborhood. And no, unfortunately, none of my guns sport German or Austrian optics.

In Part II, we’ll take about one of the biggest detriments to accuracy and that’s optical parallax.