When selecting a rifle scope, many shooters are tempted to go for the largest objective lens they can find, assuming that bigger means better. While it’s true that a larger objective lens can allow more light to enter and may produce a brighter image, this isn’t always the most important factor—especially when considering mounting height, weight, and use-case practicality.
The real key to selecting the best objective lens size is aligning it with the scope’s purpose. Whether you're running a lightweight LPVO on an AR platform or dialing in for extreme-range precision shooting, the objective lens must support the scope’s overall performance—without creating imbalance or overkill.
Why Objective Lens Size Matters
The objective lens is the front lens of the scope and directly affects:
Image brightness
Field of view
Scope height and mounting position
Rifle balance and weight distribution
Overall performance at different magnifications
However, brighter isn’t always better—especially when the scope is mounted too high or becomes too heavy for your platform. For example, mounting a bulky 50mm objective lens on a compact LPVO can severely affect ergonomics, and you won’t benefit much from the extra brightness.
Objective Lens Size Must Fit the Scope's Purpose
Here’s a helpful chart that shows typical objective lens sizes, what they’re best used for, and why they work well in those scenarios.
Objective Lens Size Guide
| Objective Size | Ideal Use Case | Scope Type | Why It Works |
|---|---|---|---|
| 24–32mm | Tactical, short-range, lightweight | LPVOs | Compact, fast, low-mounted optics for quick target acquisition |
| 36–42mm | General-purpose, hunting | All-around hunting scopes | Balanced light intake and manageable size |
| 50mm | Long-range, precision | HPVOs, precision rifle scopes | Bright, clear at high zoom and long distances |
| 56mm+ | Extreme long-range, low light | Spotting scopes, night optics | Maximum light capture and visual clarity |
Real-World Examples of Objective Lens Sizes in Use
1. Objective Lens Size for Hunting Scopes (Short to Mid-Range)
Most hunting scopes used in woodland, open fields, or hilly terrain fall within the 40–45mm range. These scopes strike a perfect balance between image brightness and overall size, making them ideal for stalking or ambush situations around dawn or dusk.
A 40mm lens gives you excellent low-light performance without adding excess weight or mounting complications to your rifle. Whether you’re hunting whitetail at first light or tracking game across varied terrain, this size works exceptionally well.
2. Objective Lens Size for Long-Range Scopes (Precision & HPVOs)
For shooters engaging targets beyond 500 yards or doing precision work, 50mm is the typical objective lens size. High-powered variable optics (HPVOs), such as 5–25x scopes, require larger objectives to maintain a clear, bright image at high magnification levels.
At long distances, target definition and clarity become critical. A 50mm lens provides just the right level of light transmission to ensure you’re not straining to see details during a shot.
3. Objective Lens Size for Tactical Use and AR-Platform Rifles
In tactical and close-quarters scenarios, smaller is smarter. Objective lenses in the 24–28mm range are ideal for LPVOs mounted on AR-15s or other short-barrel rifles.
These smaller objective lenses keep the optic low-profile, allowing for faster target acquisition, a solid cheek weld, and minimal added weight. Scopes like the GUNNR Odin FFP LPVO, available in configurations such as 1-8x24 or 1-10x28, are excellent examples. They deliver maximum performance in tight, fast-paced environments while maintaining crisp image quality thanks to high-end glass and coatings.
4. Objective Lens Size for Lightweight or Mountain Hunting
If you're hiking through rugged terrain or chasing mountain game, your scope needs to be light and compact. The ideal objective lens size here is around 32–36mm.
These lenses are commonly found on mid-powered variable optics (MPVOs) designed for ranges up to 300–400 yards. They reduce weight and bulk while still offering decent brightness—perfect for elevation gains or long-distance trekking.
Match the Scope to the Mission
Choosing the right objective lens size comes down to more than just image brightness. Here are a few key questions to help you make an informed decision:
What time of day will I be shooting? (Bright midday vs. early morning/dusk)
What range will I be engaging targets at?
How heavy is too heavy for my rifle setup?
Will a tall mount interfere with cheek weld or scope alignment?
What magnification do I realistically need for my shooting style?
Objective Lens Size Mismatches: What to Avoid
It’s easy to fall into the trap of buying a scope that looks good on paper but is mismatched for your actual shooting scenario. A 6–24x56mm scope on a lightweight .22LR is overkill. It adds weight, requires a tall mount, and doesn’t offer any real benefits at typical rimfire ranges (25–100 yards).
In contrast, a well-matched 1–6x28mm LPVO will feel nimble, fast, and perfectly suited to plinking or small game.
Final Thoughts
Bigger objective lenses do have their place—particularly in long-range and low-light conditions—but they’re not always the best choice. For most shooters, selecting the correct lens size based on practical use delivers better results than simply chasing numbers.
Smaller lenses excel in close-quarters. Mid-sized lenses offer great all-around performance. Large lenses thrive at long ranges.
Choose your optic the way you'd choose your rifle: with purpose, precision, and practicality in mind.