Two Great Truths About Optics (Craig Boddington)

I’ve written a lot of magazine articles about optics, and for several years I even wrote a continuing optics column. I don’t claim to be an expert, but I know a little bit about optics. At least, I thought I did. Just last week, at the annual Outdoor Sportsman Group “round table,” Zeiss’s Kyle Brown gave us an update on new products. He started with two very astute comments.

The first one I’ve said wrong so many times that I’m embarrassed: “Optics don’t gather light; they manage light.” The second is something that I have long believed, but Kyle said it better and simpler than I ever have: “Magnification is over-rated!”

hunting Stone ram, Kimber rifle, Leopold scope
This Stone ram was taken with a Kimber .270 WSM mounted with a 3.5-10X Leupold. Variable scopes in this power range have been the most popular for 40 years, and are still among the most versatile for much hunting.

Managing Light

The “Twilight Test” Belies the Quality of Your Optics

On the one hand, this is another way of saying the same thing, but light is what it is. Optics don’t create more light. However, in that critical half hour before sunrise, good optics do manage available light and enable you to see better than is possible with the naked eye. Note, please, the word “good.” The obvious test is to go outside at dusk or dawn, check the light with your eyes, and then look through a quality modern optic. The image through the glass will be brighter than that recorded by your eyes alone. This is done through quality of lenses and coatings.

Magnifying lenses aren’t new; the first telescope goes clear back to 1608. In 1668, Sir Isaac Newton added the first internal mirror to reflect light into the lenses. Binoculars and riflescopes go back to the 19th Century.

blacktail deer, Mossberg Patriot Creedmore, Riton scope
Donna Boddington with an excellent blacktail, taken with a Mossberg Patriot 6.5mm Creedmoor topped with a Riton 4-16x50mm scope in 30mm tube. Today’s trend is toward more powerful scopes; this is a good example of a versatile modern riflescope.

Lens Coatings Led to Revolutionary Improvements

Lens coatings, however, are products of the 20th Century, and this technology continues to evolve. If you chance across a genuine antique optic, do the same test I mentioned above. If the glass is good the image may be clear, but you will not see enhanced brightness. Lens coatings prevent available light from being reflected away and transmit it through the lenses, allowing the optic to “manage” that light.

leopard blind, hunting in a blind
The view from a leopard blind. There’s plenty of light now, but it’s going to fade quickly. This is one situation where a clear, bright scope is absolutely essential. High magnification isn’t needed, but a lighted reticle is also invaluable.

Coatings vary; many are proprietary and expensive—one reason why great optics are costly. However, if glass and coatings are more or less equal, then larger objective lenses “manage” light better than smaller objective lenses. So, a 10×50 binocular will be “brighter” than a 10×42 binocular.

Tradeoffs: Better Light Management Can Add Weight and Bulk

Unlike magnification, I will not say that brightness is over-rated… a major reason for spending extra money for extra-good optics is to gain just a couple extra minutes of visibility at dawn and dusk. Good glass costs, so you’re probably going to pay more for optics with larger objective lenses, and you will be adding weight and bulk, so there are tradeoffs.

But here’s another factor. Purely as a matter of design physics, the “European standard” 30mm riflescope allows better light transmission than the smaller American standard one-inch (26mm) scope tube. So, again with quality more or less equal, you are gaining light transmission (“brightness”) just by going to the 30mm scope, but you’re also adding weight and bulk. More frequently we are seeing 34mm and even 36mm scope tubes. Again, more weight and bulk.

When Choosing a Scope, Consider Your Priorities

European hunters are big on large riflescopes, but keep in mind that in much of Europe “shooting hours” don’t exist. Typically, we worry about a half hour before sunrise and a half-hour after sunset. Depending on cloud cover and shadows, good optics manage dawn/dusk light levels pretty well. In Europe, it’s perfectly normal to sit on stand long after dark, waiting for moonrise. This, to them, is what a big 30mm scope with 56mm objective lens is all about.

hunting at night, night hunt
North American hunters went home hours ago, but “shooting hours” are unusual in Europe. Artificial lights are rarely used, but Europeans developed bright scopes with big objectives for maximum management of natural light.

Just remember, a one-inch scope tube cannot manage light as well as a 30mm tube, and there can be diminishing returns: A one-inch tube gains less benefit from a huge objective than a scope with a larger tube. Additionally, the small, handy straight-objective scope that we think of as a “dangerous game” scope—like a 1-4x32mm—can’t manage light as well as a slightly larger scope with a bigger objective, regardless of quality. These scopes are great for stalking buffalo; more magnification isn’t needed, and max brightness is rarely an issue. However, this is also the type of scope we often put on, say, a .375 that we might take into a leopard blind, or on a .45-70 that we might use for black bear over bait. In those scenarios, light management is critical. You don’t need a “big” scope for such purposes, but you might be better served by a scope with a traditional objective bell and larger objective lens that offers better light management.

CZ Hornet .22 rifle, 4x20 mm scope, shooting targets
This CZ .22 Hornet is topped with a 1-4x20mm scope. Whether on a short-range Hornet or a .375, low magnification straight-objective scopes like this, though useful for a lot of hunting and shooting, cannot manage light as well as scopes with larger objective lenses.
Rigby rifle, Leupold scope, target shooting
A .416 Rigby topped with a Leupold VXR 2-7×33. Smaller scopes are more traditional on big rifles, but a bit of extra magnification and better light management adds versatility to the rifle. Obviously, magnification has little to do with accuracy!

Magnification is Overrated

Riflescopes are becoming more powerful, a trend sparked in part by the current interest in extreme-range shooting and enabled by technical advances that make five and six-times zoom practical. Upper magnification settings in the high teens and well beyond 20X have been around for decades, but now these “high-range” variables are increasingly common.

Obviously, there are specialized purposes for these high-powered optics. Varmint hunting for small rodents like prairie dogs requires magnification; so does extreme-range shooting, regardless of what you’re shooting at.

Larger Images Can Mean Diminishing Returns

A larger image allows you to see better and makes precise shot placement easier. I’m not going to step back into the 60s, when variable scopes weren’t quite perfected and, for good reason, were widely distrusted. Back then, our best gunwriters would pontificate that “a fixed 4X was all you really needed.” I like magnification, but there are diminishing returns.

4x scope, .270 rifle, Jack O'Connor, ram hunting
Jack O’Connor with one of his last rams, a Stone sheep taken about 1974. He used his .270 with a fixed 4X scope. At that time variables weren’t perfected and were widely distrusted. The fixed 4X was king, and experienced hunters thought 4X was plenty of magnification.

Although a larger, magnified image is easier to see and hit, what matters most is clarity of image, which comes down to quality of optics. Also, there are two problems with extreme magnification. As an inherent engineering constraint, as you increase magnification on a variable-power optic the field of view shrinks, making it more difficult to acquire the target and stay with it. With a variable-power spotting scope of, say, 20-60X, do you try to find a buck on a distant hillside at 60X? Uh, no. You start at the bottom, find it, lock in on the tripod, and then zoom in.

Craig Boddington, spotting scope, rainbow
Spotting scopes provide clear evidence that magnification isn’t everything. In order to find a distant object, we almost always start at low magnification with the widest field of view, then zoom in.

The other problem with high magnification is it magnifies everything: Heat waves, mirage, any and all wobbles, even disturbance from your heartbeat. Again, a variable spotting scope is a great example. At extreme magnification, a light breeze causes too much disturbance to resolve small objects (like antler tines and bullet holes in targets); conditions must be near-ideal to effectively use magnification much above 30X. On a smaller scale, binoculars are similar: Most people can hold a 10X binocular steady enough. Few people can hand-hold a 15X binocular steady enough to get real utility, although big binoculars are awesome when tripod-mounted.

What’s Best For Hunting? It Depends

In riflescopes there are situations where high magnification is useful, but in big-game hunting there are good reasons why the 3-9X (or thereabouts) variable has been so popular for so long! 3X won’t get you in trouble at close range, and 9X magnification is plenty for almost any shot at any range. These days, I often put a 2-7X or even 3-9X on my .375s. I don’t need the power for buffalo, but the .375 is a versatile cartridge; on smaller African antelopes there are times when the extra magnification can be handy, and a 2-7×33 or 3-9×40 “manages” light a lot better than a 1-4×32.

Craig Boddington, buffalo hunt, Afria, Sabatti
Boddington put an Aimpoint Hunter red-dot sight on his Sabatti .450 Nitro Express rifle; this buffalo was taken in Namibia at about 20 yards. Although the Aimpoint has no magnification, it’s bright and clear and truly excellent for close-range work.

On one hand, magnification isn’t always necessary. These days I often use non-magnifying red-dot sights like the Aimpoint. They are fast and bright; at closer ranges they quickly prove how over-rated magnification really is.

Buffalo hunting, Craig and Donna Boddington, Sig Sauer Scope, CZ rifle, Aimpoint scope, Blaser rifles
Craig and Donna pulled this “double play” on buffalo in 2016. She used an Aimpoint, left, on a Blaser; he used a Sig-Sauer 1-5x20mm scope on a CZ. Both were .375s, a total of three 300-grain DGX bullets expended. Clearly there was enough magnification.

 On the other hand, for hunting in more open country I do use the higher-range variables: 2-12X, 4-16X, 3-18X. Having the larger image right there at my fingertips is handy, but, honestly, it’s uncommon for me to actually use maximum magnification. In tight cover I keep scopes like these turned almost all the way down; in open country I compromise and leave them at about 6X. I can always turn up the magnification for a longer shot, but with heat waves and mirage it isn’t uncommon to be unable to use more than perhaps 12X.

hunting in Kyrgyzstan, Leupold VX6 2 12x42mm scope
High up on a mountain in Kyrgyzstan Boddington prepares for a 350-yard shot at a mid-Asian ibex. The scope is a Leupold VX6 2-12x42mm. A bit more magnification doesn’t do any harm, but this is really enough magnification for any big-game hunting.

I admit that I’m spoiled by magnification. Last year I acquired a gorgeous .270 by retired custom maker Joe Balickie. He built it some 25 years ago, and it came with the original scope, a vintage Leupold 2-7X. I would normally put a larger scope on a flat-shooting rifle like a .270. However, this rifle shoots tight little groups just the way it is, so I decided I’d leave it “original.” I took it to Namibia in July ’18. There were no “long” shots, certainly not by today’s standards, but I took several animals between 300 and 400 yards. This was an old lesson that was good to re-learn: The 7X image was plenty big enough, and although I’ve only had this rifle a year, it hasn’t yet missed. I couldn’t do any better with twice as much magnification.

vintage rifle, vintage rifle scope, Craig Boddington, hartebeest
Several decades old, this Joe Balickie .270 is topped with its original scope, a vintage Leupold 2-7X. Boddington used it in Namibia in 2018. This hartebeest was taken at about 350 yards; at 7X the image was plenty big enough.

 

When choosing optics, your environment and your priorities will help you determine what’s best for you. Magnification can be overrated, but not always, and, depending on when you hunt, it might be worthwhile to invest in expensive glass that will manage light more effectively. Remember, hunting and shooting aren’t one-size-fits-all sports; find what you’re comfortable with, stick with it, and don’t let anyone else try to force their preferences on you.