Light Transmission Myth: Why Bigger Tubes Don’t Mean Brighter Views

Light Transmission Myth: Why Bigger Tubes Don’t Mean Brighter Views

When choosing a rifle scope, especially for low-light hunting or precision shooting, it’s easy to get caught up in specs like tube diameter. But here’s the truth: the size of the tube doesn’t determine how bright your image will be.

Let’s break down two often-confused concepts—light transmission and light gathering—and show you what actually affects performance in the field.

Light Transmission: It’s Not About Tube Size

Let me ask you a question:
Which of these three scopes delivers the best light transmission?

• TORIC 1-inch
• TORIC 30mm
• TORIC 34mm

The answer? They all deliver the same. That’s becuase they all feature SCHOTT HT Glass, ED lens and our advanced multi-coated optical system. Watch the Part 2 video below to learn more…

Light transmission is all about the quality of the glass and the lens coatings—not the tube diameter. Whether it’s a 1-inch or 34mm tube, the amount of light that passes through the scope from objective to eyepiece depends on:

• Precision-ground optical glass for superior light transmission
• Advanced multi-layer coatings that reduce glare and maximize clarity
• Internal lens alignment and construction

A larger tube may offer more adjustment range, but it doesn’t make your image brighter.

PRO TIP: By increasing the size of the objective lens, the “sweet spot” (which is the center of a lens) will increase. Therefore, providing better resolution and detail which will make the image appear brighter.

Light Gathering: Where Objective Size and Magnification Matter

Now let’s talk about light gathering, which is often misunderstood.

Light gathering refers to how much light your eye can access through the scope—especially in low-light conditions. This is determined by the exit pupil, which is calculated by dividing the objective lens diameter by the magnification.

Let’s look at three TORIC scopes, all set at 10x magnification:

Notice something? The exit pupil increases with a larger objective lens—not with a larger tube. That 5.6mm exit pupil on the 34mm scope gives your eye slightly more light access in dim conditions, but it’s due to the 56mm objective—not the tube diameter.

What This Means for You

If you’re glassing at dawn, tracking game at dusk, or shooting in shaded terrain, here’s what to focus on:

• Choose scopes with larger objective lenses for better light gathering
• Prioritize high-transmission glass like SCHOTT HT found in all TORIC scopes for superior light transmission
• Don’t assume a bigger tube means a brighter image—it doesn’t

All three TORIC scopes mentioned above are excellent long range options. The right choice depends on the desired weight of your set-up, adjustment range, and low-light preferences—not the myth of tube diameter brightness.

Explore the Full Line of TORIC Rifle Scopes

At TRACT, we design scopes with purpose—balancing optical performance, rugged construction, and real-world utility. Whether you’re running a lightweight 1-inch tube a 30mm long range model or a 34mm beast, you’re getting elite performance where it counts.

See the full line of TORIC Rifle Scopes at TRACToptics.com