Super-telephoto shooters, rejoice! Two groundbreaking lenses have recently burst onto the scene—and they’re rewriting the rules of long-lens photography. Whether you capture action sports, wildlife, or any style of photography that requires quite a bit of reach, these two brand-new lenses are something to be excited about.

Here at Backcountry Journeys, we're quite excited about the brand-new Sony FE 400-800mm f/6.3-8 G OSS and the Sigma 300-600mm f/4 DG OS Sports—both world's firsts in their own right, and both redefining what’s possible for wildlife, sports, and nature photographers. Whether you're a Sony shooter looking for extreme reach, or a pro craving the performance of multiple primes in one lens, these new releases offer exciting new choices for today’s demanding photographers.

Let’s dive into each lens and explore what makes them so special.

Sigma 300-600mm f/4 DG OS Sports:

Prime-Like Performance in a Versatile Zoom
Sigma’s newest flagship for the Sports line is a marvel of engineering and performance. Offering a constant f/4 aperture, internal zoom, and an exceptional level of build quality, the 300-600mm f/4 is designed for professionals who want the flexibility of a zoom without sacrificing the image quality and speed of prime lenses.

SPECS:

• Full-Frame Format | Aperture f/4 to f/16

• Constant f/4 Aperture

• Internal Zoom and Internal Focus

• High-response Linear Actuator (HLA) AF Motor

• 5.5-Stop Optical Stabilization with OS2 Algorithm

• Weather-Sealed Magnesium Alloy Construction

• Drop-In 40.5mm Filter Holder

• Configurable Function Ring (Focus Preset / Power Focus)

• Rotating Arca-Type Tripod Collar

OVERVIEW:

Versatile Range with Prime-Level Sharpness
Covering 300-600mm with a fixed f/4 aperture, this lens can easily replace a 400mm and 600mm prime lens in your bag—while still delivering professional-grade clarity, contrast, and speed. Perfect for wildlife, birds, and field sports, the Sigma’s constant f/4 allows for greater control over depth of field and more confident shooting in lower light.

Fast Autofocus & Smart Controls
The HLA-driven AF motor is lightning-fast and surgically accurate—ideal for locking onto distant, fast-moving subjects. The lens also includes an innovative function ring, which can either jump to a preset focus distance or allow smooth power-focus transitions, great for video work.

Robust Stabilization and Handling
With 5.5 stops of compensation powered by the OS2 algorithm, the Sigma handles like a much smaller lens. You can shoot handheld in good light or pan smoothly using Mode 2 for action shots.

Field-Ready Durability
Built to withstand brutal environments, the lens features magnesium alloy construction, dust/splash resistance, and thermal insulation paint to help regulate heat in tough conditions.

This lens is a serious contender for pros who need reach, quality, and field reliability.

Sony FE 400-800mm f/6.3-8 G OSS:

The Longest E-Mount Zoom Yet
Sony has finally delivered what its wildlife and birding community has been asking for—a native E-mount lens that reaches 800mm without teleconverters. Lightweight for its class, beautifully sharp, and packed with smart stabilization, the FE 400-800mm f/6.3-8 G OSS is a dream lens for long-distance shooters, and a first-of-its-kind offering in the Sony ecosystem.

SPECS:

• Full-Frame Format | Aperture f/6.3 to f/45

• G Series Optical Quality

• 400-800mm Zoom Range (1120mm / 1600mm w/ Teleconverters)

• Dual Linear Motors for Fast AF

• Internal Zoom Design

• Optical SteadyShot Image Stabilization

• Rotating Tripod Collar with Fixed Mount

• 1.4x & 2x Teleconverter Compatible

• Dust and Moisture Resistant

OVERVIEW:

Unprecedented Reach for E-Mount Shooters
This is Sony’s first zoom lens to hit 800mm, and with teleconverters it can reach up to a mind-blowing 1600mm. The lens fills a major gap in Sony’s lineup, offering wildlife and nature photographers a long-reach solution without requiring third-party lenses or cumbersome primes.

Quick Handling and Refined Ergonomics
Despite the long focal length, the Sony is surprisingly manageable, weighing just 5.45 lb. It features a short rotational throw zoom ring for fast composition changes and includes three customizable focus hold buttons for effortless control in any orientation.

Stabilized for the Long Haul
Sony’s Optical SteadyShot is fine-tuned for this lens’s long reach, using a gimbal-like mechanism to counteract camera shake effectively—even when handholding at 800mm.

Built Tough with Premium Optics
Six ED elements, an 11-blade circular diaphragm, and a robust dust- and moisture-resistant design make this lens not only capable of delivering stunning image quality, but also dependable in demanding outdoor conditions.

If you’re a Sony user who has been longing for a native 800mm lens with zoom versatility, this is the solution you’ve been waiting for.

The Bottom Line: Two Super-Telephoto Titans That Redefine the Field

The Sigma 300-600mm f/4 DG OS Sports lens and the Sony 400-800mm f/6.3-8 G OSS lens are not just impressive—they’re revolutionary. Sigma’s offering delivers unmatched flexibility, constant aperture, and prime-like performance. Meanwhile, Sony’s new zoom breaks barriers by reaching 800mm natively, offering unmatched compatibility and stabilization for the E-mount system.

These lenses reflect a new era of super-telephoto capability—where reach no longer means compromise. Whether you're a bird photographer tracking distant avians at dawn, or a sports shooter capturing fast-paced action from across the field, these lenses give you the power to go farther, faster, and with more precision than ever before.