Two things help to ensure that a scope offers the brightest image possible to the shooter’s eye: improvement of light transmission and glare reduction. Of the two, reduction of glare is perhaps more important, as glare can negate all the effort taken to enhance light transmission. Of course, before we can understand how it is reduced, we must understand what it is. The light that enters the scope is focused into a small beam so that it can easily pass as undisturbed as possible through each lens of the scope and out the eyepiece lens to the shooter’s eye. Any light not focused into this beam within the scope will reflect off of the interior surface of the scope or a lens and become glare. Glare disturbs the focused light beam passing through the scope from the image to the eye.
“But light is just light, isn’t it? Won’t it just add the light back into the beam?”
Although this would make sense, it does not work that way. Think of it this way: suppose you were showing a movie from a projector in a dark room. While the room lights are turned off, the movie projected onto the screen will be clear and the picture crisp. Now imagine someone turns on the lights; what happens to the image on the screen? It becomes faint and difficult to see. That’s because the light in the room is now disturbing the light beam from the projector, just the way glare in a scope disturbs the light beam within the scope. In both cases, the stray light washes out both the brightness and the color of the image.
Without glare, your eye gets the picture projected through the scope undisturbed. With glare, the beam is disturbed and the image is hard to see. So it’s easy to see why glare reduction is so important to the production of a good image in a scope.
Now here’s how it’s done.
Glare can be reduced in a scope by eliminating all reflective surfaces inside the scope, by the use of light baffles within the scope, and by applying anti-reflective coatings to the lenses of the scope. The first thing to do to prevent glare is to ensure that there are no reflective surfaces in the interior of the scope. This is done by the use of flat, matte black finishes on all interior surfaces of the scope. Light baffles are rows of grooves that are placed in crucial areas of the scope to further prevent any stray light from reflecting off a surface.
However, we are still left with the fact that within a scope there are a dozen or so surfaces that must be highly polished and perfectly smooth; the lenses. That’s where the anti-reflective coatings come into use. Anti-reflective coatings are chemical compounds, such as Multicoat 4, that when applied to a lens prevent light from reflecting off the surface of the lens and enhance the amount of light focused through the lens. All these things combine to offer an image that is clear with vivid color and strong contrast to the eye.
Glare can be reduced in a scope by:
- Eliminating all reflective surfaces inside the scope
- Using light baffles within the scope
- Applying anti-reflective coatings to the lenses of the scope
Let’s review: glare is stray light within a scope that disturbs the light beam carrying the image as it passes through the scope. Glare can be reduced by the use of non-reflective surfaces and light baffles inside the scope, and the use of anti-reflective coatings on the lenses of the scope. A glare free image is crisp, the colors are vivid, and the contrast is strong. The important thing to remember is that glare can ruin a scope’s image so always choose a scope that uses these glare reduction techniques in its design.