To most hunters, optics are magic black tubes. Binoculars conjure deer. Riflescopes place bullets across great distances. But how do you tell a good optic from a lousy one without relying on price or brand? You measure its performance with scientific repeatability, then you give it to a group of hardcore hunters and shooters and ask for their practiced assessment of details like focus knobs (precise or mushy?), eyecups (do they stay or stray?), and image quality (are the edges of the picture crisp or blurry?). Judgments are made. Scores are recorded. Then we argue over which we think are the best optics of the year.
OL’s Optics Test has two parts. The first is objective: We evaluate the optical quality of each submission on a resolution range, using the standard of the industry–a 1951 U.S. Air Force resolution target–to measure the optic’s ability to define ever-smaller black-and-white lines. We test resolution twice with two sets of eyes and average the results.
We also mount riflescopes to a device that lets us track the precision of windage and elevation adjustments and the ability of a scope to retain its point of aim across its magnification range.
We have one other objective test, one that makes our test the best in the business. It’s our low-light evaluation, in which we position a team member 100 yards from a blacked-out room and ask him to slowly turn a black-and-white resolution target as twilight fades to night. Meanwhile, team members in the room glass the target through open windows and record the moment they can no longer define the direction of the contrasting lines. The longer an optic “sees” into the dusk tells us a lot about its light transmission and optical clarity. We repeat this test on successive nights and average the results.
Objective scores make up half of an optic’s overall rating. The other half is a lot more fun: It’s our subjective testing, in which we spend a week using the optics like any hunter would: glassing distant deer and mountains, detecting optical flaws such as spherical aberration, color flaring, and sharpness of image. And we pay special attention to a metric that all hunters recognize: How comfortable is the optic to look through? The ones that are easy on the eyes often are the ones that end up with the best scores.