The Sony FE 400-800mm F6.3-8 G OSS ($2,899.99) is as big and long a zoom lens as you'll find for any full-frame camera, and enters the E-mount system as the longest focal length entry yet. Its extremely narrow angle of view brings distant subjects into view, an ideal choice for wildlife photography in general, and small, skittish critters like birds especially. We like its mix of internal zoom, fast focus, effective stabilization, and exceptional telephoto reach, but realize it's a hefty lens to carry through the wilderness. Photographers who care most about wildlife imaging should snap this lens up, though we continue to recommend the more affordable Sigma 150-600mm F5-6.3 DG DN OS Sports ($1,499.99) as our Editors' Choice telezoom due to its aggressively low pricing and similar picture quality.

Design: Internal Zoom Makes Up for a Bulky Barrel

Telephoto lenses, especially those that reach the exceptionally long 800mm focal length, are big, bulky propositions by definition. Quite a bit of glass is required to realize such a narrow angle, offer zoom, and capture images with sharp detail and controlled aberrations. The FE 400-800mm is a long one, requiring a 13.6-by-4.7-inch barrel to hold its 27-element/19-group optical formula, and tips the scales at 5.5 pounds.

(Credit: Jim Fisher)

It's a big lens for sure, though not out of character for telephoto peers. Sigma's value 150-600mm Sports (10.5 by 4.3 inches, 4.6 pounds) and the faster-focusing 60-600mm F5-6.3 DG DN OS Sports (11.0 by 4.7 inches, 5.5 pounds) are both a bit smaller on paper, though the 400-800mm is a little easier to use in practice because its zoom is all internal. That means that it only takes a light touch on the zoom ring to change the focal length, and the lens never gets any bigger or smaller.

The telescoping Sigma zooms require more torque to manipulate, and both become longer at 600mm than the FE 400-800mm. Internal zoom is an uncommon design choice, but not unheard of; the Sony FE 200-600mm F5.6-6.3 G OSS (12.5 by 4.4 inches, 4.7 pounds) also features a rigid barrel with internally zooming optics. If you want a smaller telephoto lens, you'll either need to forgo a zoom and get a prime lens like the excellent Sigma 500mm F5.6 DG DN OS Sports (9.2 by 4.2 inches, 3.0 pounds) or a shorter zoom like the Tamron 150-500mm F5-6.7 Di III VC VXD (8.3 by 3.7 inches, 4.1 pounds).

Lucky grabs aside, a 500mm focal length is the minimum I'd consider to be useful for a wildlife lens. It's fine for larger critters, but a little short for songbirds. Longer focal lengths are even better for animals in nature, though they can be too tight for field sports, especially if you have sideline access. A Sony representative describes the FE 400-800mm as a lens that's "not just for birds and wildlife, but mostly for birds and wildlife," and for what it's worth, I think that's a spot-on assessment.

(Credit: Jim Fisher)

The FE 400-800mm is part of Sony's G series, the system's second-highest class of optics behind G Master (GM). Despite not earning the highest grade, the 400-800mm boasts exceptional construction. It uses magnesium, a metal that's both tough and lightweight, and incorporates internal seals to prevent dust and moisture from getting inside.

(Credit: Jim Fisher)

The front element includes anti-smudge fluorine, which is a nice touch as its large 105mm filter thread makes even a simple UV protective filter an expensive prospect. A reversible lens hood is included and provides plenty of protection for the front element if you use it. The hood includes a sliding cut-out window so you can adjust the orientation of a circular polarizing or variable neutral density filter without having to first remove the hood. It's a shame Sony couldn't work a rear filter system into this lens, an element the brand has only included in exotic tele primes like the $13,000 FE 600mm F4 GM OSS so far.

A tripod foot is a must-have for such a long lens as it is far too front-heavy to use with a camera's tripod socket. The 400-800mm's foot is placed under its center of gravity, so it's easy to balance on a gimbal tripod head, with the added benefit that the foot works well as a handhold when carrying the camera. The collar rotates a full 360 degrees and includes visual marks to line it up with the lens at plumb 90-degree angles, but no click stops.

(Credit: Jim Fisher)

I have two complaints about the foot. One, it'd be nice to see Sony embrace the Arca-Swiss tripod standard and add dovetail cuts so that it could mount directly into compatible tripod heads without the need for a quick-release plate as Sigma and Tamron have done. The second is comparatively minor: The foot requires a hex screwdriver to remove, whereas most lenses let you remove and attach the foot without tools.

Both of Sony's rear teleconverters work with the FE 400-800mm, but given its narrow F6.3-8 aperture range, you'll want bright, sunny weather if you're looking to extend the reach even further. With the FE 1.4x attached, the lens becomes a 560-1,120mm F9-11, and with the FE 2x, it's an 800-1,600 F13-16. I struggled to keep the ISO under control without teleconverters under dull gray winter skies, so the dim f-stop really makes the FE 400-800mm a sunny weather lens.

(Credit: Jim Fisher)

Handling and Autofocus: Pro Controls and Fast Linear Focus

There's no getting around the FE 400-800mm's size, but as large as it is, I didn't find the lens to be unmanageable for handheld capture. Its 5.5-pound weight is on the upper end of what I consider reasonable, but isn't too far off from other telezooms; the Sigma 60-600mm Sports is roughly the same weight. Sony did a good job keeping the weight fairly centered over the tripod foot, too, so it feels natural to support the lens and operate the zoom ring with your left hand while you hold and operate the camera body with your right hand.

(Credit: Jim Fisher)

The zoom ring is a real treat to use, too. The internal zoom optics don't require as much torque to move as telescoping zooms, so you can set the focal length with just your fingertips. This makes for quicker, quieter operation in the field, allowing you to set the zoom without startling an animal, and is also handy for video shots that incorporate a zoom. The manual focus ring is just as comfortable to turn and works in any focus mode, so you always have the option of giving the camera a little help if its autofocus system has a hard time locking onto a bird hiding in branches, for instance.

(Credit: Jim Fisher)

The zoom also includes three copies of the Focus Hold button at the top, bottom, and left side of the barrel, in between the two focus rings. The Focus Hold button locks focus in place by default but may be reconfigured via the camera menu if you prefer to have it perform another function (AF-ON is a popular alternative). Just understand that all three copies of the button are tied to the same configurable function; you can't remap them independently. The logic behind the repetition is so that the button is in the same relative place regardless of whether you're holding the camera in landscape or portrait orientation.

(Credit: Jim Fisher)

The lens also has a large panel of toggle switches, five in total. AF/MF changes between auto and manual focus, and Full Time DMF On/Off enables or disables the Direct Manual Focus, Sony's name for the aforementioned manual focus override mode. There's also a Focus Limiter that restricts the autofocus to either close (minimum distance to 10 meters) or distant (8 meters to infinity) and has a Full setting for unrestricted autofocus. I appreciate the feature, as it prevents the lens from hunting for focus in situations where you know you'll be working closer to or far away from a subject. The remaining switches adjust optical stabilization: One lets you turn it on or off, and the other changes stabilization between Mode 1 (for static subjects), Mode 2 (for horizontal panning shots), and Mode 3 (to pan with subjects moving both vertically and horizontally).

(Credit: Jim Fisher)

I used the lens exclusively with the 60MP a7R V for field testing, as it's not only Sony's highest-pixel camera, but it also boasts its latest autofocus system and supports 10fps continuous capture. The FE 400-800mm drives focus in an instant, and like many of Sony's telephoto lenses, it uses a pair of XD Linear focus motors for speedy, accurate results. The 400-800mm's focus speed is a major advantage over the Sigma 150-600mm Sports, which uses a slower STM system that can miss focus if a subject is moving toward or away from camera at speed.

(Credit: Jim Fisher)

Other third-party lenses can keep up with the 400-800mm in focus speed, however. Both the Tamron 150-500mm and the Sigma 60-600mm Sports use similar linear focus systems that provide a speedy response. But understand that Sony restricts third-party lenses from using the fastest drive speeds on its a1 and a9 series camera bodies. You can use the FE 400-800mm with the a9 III for 120fps capture with focus and exposure for each frame, while any Sigma or Tamron lens is restricted to 15fps with continuous focus. If you use a camera capable of very high drive speeds, it is a compelling reason to buy a Sony over a third-party lens.

(Credit: Jim Fisher)

The FE 400-800mm has a pretty decent close-up focus capability, setting itself apart from super telephoto primes, which typically use optical formulas that can't focus at macro distances. At 400mm the zoom locks onto subjects as near as 5.6 feet, good enough to capture them at 1:4.3 life-size. At 800mm the lens focuses to 11.5 feet. It's not often that you can get that close to wildlife, but in situations where you end up close and personal with a critter, you can get the shot. Compare this with Sony's premium FE 600mm F4 GM OSS prime, which can only get to 14.8 feet (1:7.1 reproduction), though, to be fair, it gathers four times the light when compared with the FE 400-800mm and proves to be sharper too. Of course, you'd expect that, given its $13,000 price.

(Credit: Jim Fisher)

Image Quality: Requires Ample Light for Best Results

The FE 400-800mm shares a trait in common with most extreme telephoto telezooms: a narrow maximum f-stop. Its f/6.3-8 aperture is well-suited for use outdoors under natural light and falls short of what you want for interiors. Indoor use isn't a huge concern with this lens, as you'll need quite a big space to use it practically. If you have the need for a brighter telephoto lens, you'll either need to spend big on a prime like the FE 600mm F4 or the FE 300mm F2.8 or go with a much shorter zoom like the 70-200mm F2.8 GM II.

(Credit: Jim Fisher)

Primes aren't just brighter, they tend to be sharper too. I tested the FE 400-800mm's resolving power with the 60MP a7R IV and used Imatest software to check. At 400mm f/6.3 scores around 3,000 lines on our telephoto lens test chart, and improves to 3,400-3,700 lines at f/8-16, before falling off at f/22-36 (2,400-1,300 lines). Scores are generally higher at the midpoint of the zoom, 600mm, the lens scores 3,700 lines at f/8 and improves to 4,000 lines at f/11. At 800mm, the lens scores 3,000 lines at f/8 and manages 3,700 lines at f/11. These scores are in line with other zooms like the Sigma 150-600mm Sports and the Sony FE 200-600mm, but fall shy of prime results. The FE 600mm F4 delivers ideal resolution with our telephoto chart (4,400 lines at f/5.6).

(Credit: Jim Fisher)

Numbers are one thing, but what does that mean in plain language? Like its contemporary telezooms, the FE 400-800mm shows very good detail but may not pull out the finer results you see from a prime. If you pixel peep a photo of a songbird snapped with the FE 400-800mm, you'll have a hard time making out fine detail in the feathers, while with a prime like the FE 600mm F4 or Sigma 500mm F5.6 Sports, you can often identify each feather tip. If you have the light, stop down by about one stop (f/8 at 400mm, f/11 at 800mm) and use a brisk 1/800-second (or faster) shutter speed to ensure a capture that's not affected by hand shake or subject motion.

(Credit: Jim Fisher)

Primes also have an advantage in light gathering, allowing your camera to work at a lower ISO and produce cleaner images. Zooms have their place, as the ability to change your angle is valuable for capturing more varied scenes and also for finding a small animal in the wild—zoom out to 400mm to get it centered and zoom back in to 800mm for a photo. And, as mentioned, telezooms typically focus much closer than telephoto primes.

(Credit: Jim Fisher)

The lens shows some pincushion distortion through its entire zoom range when using your camera for Raw format images, but in-camera corrections automatically compensate for the effect for JPGs and videos. For this lens, distortion correction may be turned off if you prefer. The pincushion effect is pretty minor overall and doesn't really detract from the type of photos you're most likely to make with this lens, so I'd consider any correction optional and a matter of personal preference. Adobe doesn't yet have a distortion correction profile for this lens, but I expect that to change with the next Lightroom Classic release, as the editing app is updated every few months to support new cameras and lenses. In the meantime, a -5 distortion correction slider adjustment straightens lines appropriately in Raw images.

(Credit: Jim Fisher)

Photographers often associate blurred backgrounds with prime and brighter f/2.8 zoom lenses, but it doesn't take an extra-wide f-stop to get bokeh with a super telephoto zoom. The 400-800mm blurs backgrounds behind subjects readily and can also blur away foreground obstructions to some degree. The blur is generally smooth, sidesteps soap bubble highlights, and avoids false color from longitudinal chromatic aberration (LoCA) effectively for clean, distraction-free bokeh in most instances.

(Credit: Jim Fisher)

Verdict: Birders Will Crow About This Lens

The FE 400-800mm F6.3-8 G OSS is a specialized lens that caters to a narrower audience than many, namely birders and wildlife photographers. It's ideal for creators who like to capture wildlife in its natural habitat and is a fantastic option for a safari or day out at the zoo as well. Birders especially should consider this lens for its extra zoom power, which goes beyond what most consumer telezooms provide. We continue to recommend the Sigma 150-600mm F5-6.3 DG DN OS Sports as our Editors' Choice telezoom for Sony cameras as it comes in at about half the price and provides similar picture quality, albeit with slower autofocus. But if a 600mm zoom isn't long enough for the photos you want to take, the FE 400-800mm F6.3-8 G OSS is an excellent alternative.