Sony FE 400mm F4.5 GM OSS Review

I cannot tell you how many times I’ve heard people request high performing telephoto prime lenses with smaller maximum apertures, smaller size, and smaller prices. Traditionally there has been a huge gap between telephoto zooms (typically costing $1000-3000) and the fast telephoto prime lenses that frequently cost $10,000+. Sigma helped bridge that gap in 2024 with their $3200 500mm F5.6 OS | SPORT lens (my review here), but on Sony third-party lenses are subject to certain limitations, including reduced burst rate (no more than 15FPS with full autofocus) and a restriction on teleconverters. That makes the new Sony FE 400mm F4.5 GM OSS and 600mm F6.3 OSS all the more interesting. Imagine two very high performing telephoto primes that weigh under a kilogram each and cost, respectively, $2699 USD and $3699 USD that are fully compatible with Sony’s highest burst rates (up to 120 FPS on the α9III) and the 1.4x and 2x teleconverters. I suspect Sony’s newest lenses are going to make a number of wildlife, bird, and even sports photographers very happy. Let’s explore why…

https://youtu.be/TzK4s77jB6U

Thanks to Sony USA for sending me a review loaner of this lens. As always, this is a completely independent review. *The tests and most of the photos that I share as a part of my review cycle have been done with the Sony a7RV and the Sony A1 II. You can visit the product page for the 400mm F4.5 GM OSS here.

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SUMMARY: The Sony FE 400mm F4.5 GM OSS lens offers impressive performance, combining a lightweight design with high optical quality at a more approachable price point compared to traditional high-end telephoto primes. Weighing under a kilogram and costing approximately $2699, it maintains excellent autofocus capabilities and is compatible with teleconverters, making it versatile for various photography scenarios. The lens delivers sharp, vibrant images with beautiful bokeh, appealing especially to wildlife and sports photographers. Overall, it presents a strong option for those seeking high performance without the bulk and cost of larger lenses.

Strengths:

Lightweight Design: Under 1 kg, making it easy to carry.
Versatile Compatibility: Works well with 1.4x and 2x teleconverters.
Excellent Autofocus: Fast and reliable, suitable for high-speed photography.
Outstanding Optical Quality: Sharp images with beautiful color and smooth bokeh.

Weaknesses:

Not Arca-Compatible: Requires an additional quick release plate for tripod use.
Limited Maximum Aperture: While effective, it doesn’t match the light-gathering ability of faster primes (e.g., F2.8).
Small Focus Throw: Less range for precision focusing in certain situations.

While most people will always be attracted to the longer lens, I’m personally more intrigued by the 400mm F4.5 GM. The 400mm F2.8 GM OSS costs $13,000, and while it is bright, fast, and incredible, it is (in addition to costing as much as a nice used car) nearly 3 kilos in weight and nearly 360mm in length. The 400mm F4.5 GM weighs 994g, is 242mm long, and is still bright enough to work reasonably well with both telecoverters. Add a 1.4x teleconverter, and you’ve got a 560mm F6.3 lens that can focus lighting fast and easily produce images like this:

And while 2x teleconverters come with more optical compromises, you can attach one and get a 800mm F9 lens that can still produce fairly stunning images.

That’s a lot of versatility for a prime lens that is priced well under $3000 and can deliver outstanding detail:

…while also being capable of producing gorgeous bokeh:

I absolutely loved the new Sony 100-400mm F4.5 GM OSS (my review here), but that lens costs $4300 USD and weighs 1840g (twice as much), so if you are considering the zoom just to get that 400mm F4.5 combination, this new prime is going to make a lot more sense.

Let’s take a closer look…

Build and Handling

If you are familiar with telephoto primes and zooms, you know that they are a big and heavy lot. You typically get a LOT of attention when you show up with a big telephoto lens, and while these two new primes from Sony aren’t what anyone would call small, they are significantly smaller than my longtime telephoto companion – the Sony FE 200-600mm.

That makes a huge difference in where a lens like this can be stored and how it can be carried. I was shocked to discover that I was able to fit both Sony primes, an α1 II camera body, and both the 1.4x and 2x teleconverters in a Peak Design Medium camera cube.

That was very impressive to me. I went to the shooting gig to track a champion Golden Retriever being advertised for stud with just that configuration.

More specifically, the 400mm F4.5 GM is 108mm (4.25″) in diameter and 242mm (9.52″) in length.

On my scale, the lens weighs 998g with the tripod foot, caps, and lens hood removed (the official weight is 994g, or 35oz). Add all of those back in and the weight goes up to 1216g.

The lens comes across as feeling very lightweight for its size, and the balance is superb due to Sony designing the lens with only one element towards the front, meaning that most of the glass is near the camera body. It is that much easier to support the front of the lens as a result, making this a very easy lens to use handheld.

The front filter thread is a large but reasonably common 95mm size.

Some of the higher end primes and zooms have a drop-in filter holder as well, but that is absent here.

The aperture iris has 11 rounded blades, but there is no manual aperture ring (that isn’t present on the 400mm F2.8 GM, either).

We do have a full bank of controls, however, including:

An AF | MF switch
A switch to control whether or not you want DMF (full time manual override) enabled
A two position focus limiter (full range or removing focus under 7 meters to eliminate any aperture racks or the focus catching on a closer object)
An ON | OFF for the OSS (Optical Steady Shot)
A three position mode switch for the OSS. 1 being standard, 2 for panning, and 3 being “dynamic” or prioritizing stabilization only at image capture.

Also present are a total of 4 Fn (custom) buttons distributed around the barrel in a ribbed section to the front. These all share one common function (whatever you assign from the in the camera) but are situated on all four points so one is always easily accessible in all shooting positions.

Also included is Sony’s customizable function ring (the narrow ring above), which can be assigned various functions like programming a preset focus position (great for sports), power focus, or even something like switching between full frame and APS-C mode.

The manual focus ring is broad and nicely beveled to make it ergonomically pleasing. Despite the size of the ring, the weight is actually fairly light, making it easy to make one finger adjustments. I do find that the focus throw (range) is a bit smaller than I’d like for precision in some situations.

The 400mm F4.5 GM has a typical GM-level thorough weather sealing, starting with a gasket at the lens mount and internal seals all throughout. The front element has a special fluorine coating to help repel oils and moisture.

The tripod collar is fully rotatable and can be controlled by a simple tension knob. There are no “detents” or clicks, but rather the collar rotates freely, so be sure to use the alignment dots to line things up properly

The foot is (as per usual for Sony) NOT Arca compatible, meaning that I have to add a quick release plate before mounting it on a tripod.

The collar itself is integrated and not removable, but the foot itself can be easily removed if you want to travel slimmer and lighter.

As noted earlier, the 400mm F4.5 GM is fully compatible with Sony’s 1.4x and 2x teleconverters, giving you a 560mm F6.3 combination with the 1.4x teleconverter.

Adding the 2x teleconverter gives you an 800mm lens with a maximum aperture of F9.

The minimum focus distance is 2.5m (8.2 feet), and the resulting magnification from the bare lens looks like this:

That gets you a little closer than the 400mm F2.8 GM (2.7 meters), and the magnification level seems to be somewhere around 0.18x. I found that close focus results were nice and crisp just like everything else around the optical performance.

Both the new 400mm and 600mm GM lenses come with nice, zippered cases that are identical in size. The slightly shorter length of the 400mm lens comes with a nice benefit, however. The lens will fit in the case with my camera attached, which makes for a convenient transport option. I even strapped it to the rear carrier on my e-bike when going out on trails to try to find subjects.

And finally, that price tag of $2699 USD, while not cheap, feels like an absolute bargain for a lens like this. It obviously doesn’t have the light gathering potential of the big 400mm F2.8 GM, and it backgrounds won’t be as blurred, but this is a high-performing lens in every sense. It is sharp, focuses lighting fast, and tracks effortlessly. Combine that with a lens that is easy to bring along handheld, and you’ve got an absolute winner.

Autofocus

Sony’s XD (Xtreme Dynamic) Linear Motors are powerful, quiet, and confident, and the 400m F4.5 GM comes with two of them, assuring that focus is very close to instant. That allows you to pick up birds in flight effortlessly and nail focus.

One of the big points of emphasis for Sony is that you are getting the same kind of sophisticated autofocus in the 400mm F4.5 GM as you are in the much-more-expensive 400mm F2.8 GM. Autofocus is very near instant in my formal tests, and more time is spent with long focal lengths in actually centering your target in the narrow angle of view than actually focusing.

A bluebird and some grackles were jetting across my yard, and while I didn’t have time to set everything up the way that I would like, I still snapped off a string of shots of them shooting across the yard against very difficult (busy) backgrounds. The photos themselves are too busy to be special, but I was impressed by how good autofocus was despite the complexities of the scene and my having less-than-ideal setup on my camera.

When I was actually set up and prepared to shoot, I don’t think I missed a shot with the 400mm F4.5 GM mounted on my α1 II. Every shot in the long bursts of over 100 frames were perfectly focused, allowing me to focus on the poses I liked the most.

I shot a lot of panning shots, as the trainer/breeder wanted profile shots to show the young stud’s power.

Focus worked well, as did the stabilization in Mode 2 (for panning).

What’s more, I found that focus was flawless with the Sony 1.4x TC attached as well (560mm F6.3).

That was true even when I grabbed shot shots (with the 1.4x) from the rear of him chasing back to the trainer (and scaring up a butterfly as he passed!)

I used the lens with the Viltrox 2x teleconverter, and while this isn’t an “official” pairing, autofocus remained excellent. I was shooting the sequence for the trainer where they were practicing the “trot” done with the trainer and dog at shows. Here’s a frame at 800mm, F9.

In more casual shots, it didn’t matter whether I was capturing a tiny parachuter soaring through the sky…

…a motorcyclist flying by…

…or an ATV’er fording a stream…

…focus was always flawless. This is a great focusing lens.

And it is designed to keep up with your Sony camera, no matter how fast its burst rate is.

Video AF

Telephoto lenses are much more niche products for video work because they are so extreme. They might be used for wildlife videography, perhaps for sports, but no one is running around with a 400mm and 600mm prime on a gimbal!

That being said, Sony emphasizes that the focus system here is capable of full time tracking up to 120FPS during video production, and I shot a few 4K120 action clips during my sequences to test if focus kept up.

It did. Here’s one grabbed frame from running bursts.

And here’s another.

Being able to grab specific moments with good detail from 4K120 video could obviously be very useful.

Likewise the ability to choose the moment when the little wave was cresting behind this seagull was also interesting.

Focus was solid in all these situations, and focus pulls are smooth and confident.

Sony 400mm F4.5 GM Optical Performance

This may be Sony’s smaller, cheaper, option, but it still has a robust optical design of 22 elements in 16 groups, with include 3 Super ED (Extra-low Dispersion) and one ED element. I don’t yet have the MTF charts on the lens in hand, as I’m reviewing it ahead of Sony making any such materials available. I’ve seen those MTF charts in a Sony briefing, however, and they are stunningly good. What matters more is that real world results are also stunningly good.

The full shot tells you the whole story here. Not only is this lens very sharp and beautifully corrected (see the absence of an fringing along the rough of fur at the top of the crop) but the rendering is beautiful. The transition to defocus is smooth and creamy. Images have an absolute pop to them.

Colors are rich and saturated but without being garish in any way.

Testing long lenses is much more complicated for independent reviews like myself, as the amount of space you need to test 400-800mm (as I’m doing here by the time teleconverters are added) is significant. Here’s how far away I am when testing for 800mm.

Being outdoors introduces a lot of variables that I can’t control – temperature, lighting, air movement, etc… I do my best to compensate for all of these factors, but I also lean a little harder into real-world examples for that reason.

That being said, here are some of my chart findings.

First of all, the 400mm F4.5 GM needs basically zero optical correction for vignette and distortion. I found I could tweak the sliders bit a few percentage points and maybe get a tiny improvement, but it really wouldn’t be seen in a real world situation.

Adding the Sony 1.4x teleconverter adds a tiny amount of barrel distortion (+4 to correct) and vignette (+21), though the vignette is still so negligible as to not need correcting. Adding the Viltrox 2x teleconverter actually reduces the barrel distortion (+2 to correct) while the vignette (+22) is about the same.

This is a lens that tolerates teleconverters very, very well. This image, for example, has had zero corrections and was taken with the 1.4x teleconverter. I see no need for vignette correction in those foreground corners that still look nice and bright to me.

Longitudinal Chromatic Aberrations (LoCA) shows up as colored fringing before and after the plane of focus and tends to be more pronounced in large aperture lenses. There is zero issue with LoCA here. Transitions on high contrast areas and shiny bits are perfect.

Lateral Chromatic Aberrations (LaCA) show up as color fringing on either side of contrast objects near the edge of the frame. No problem here, either, as I see no fringing in the transitions from black to white.

This is a beautifully corrected lens.

So how about sharpness and contrast? I’m using a 61MP Sony a7RV for these tests, and crops will be shown at 200% level of magnification. I’ve worked hard to eliminate the variables that can impact sharpness results, though I’m sure my results won’t be perfect.

Here’s the test chart.

Taking a look at the deep crops from the center, midframe, and lower right corner, we see nothing but excellence. The bills on my chart don’t like the humidity outside, but the detail and contrast looks amazing everywhere.

Stopping down to F5.6 produces no apparent improvement in the center or midframe, but I do see some additional detail in the corners.

Sharpness is consistent through F8, though after that point you will definitely start to see some softening due to the effects of diffraction. By F32 (minimum aperture), the image is looking quite soft.

Let’s just say that sharpness will never be a problem.

Here’s another sharpness example.

Adding the Sony 1.4x teleconverter comes with only minor sharpness impact. Here’s a comparison to the bare lens all across the frame:

2x teleconverters always have more impact on the optics than 1.4x teleconverters, and the maximum aperture of F9 this combo induces is further above the diffraction limit, which also reduces sharpness. Chart results are still acceptably good, however.

In a few real-world examples you can see that the fine the detail isn’t quite as good, though that’s only really apparent when looking at high magnification levels.

The results would certainly be fine at a global level, though it could be argued that shooting in APS-C mode might give you slightly better results (or just cropping).

So how about rendering? We can see from the above example that the scene was complicated – a “grove” of ferns all densely packed together, but the 400mm F4.5 GM still handles the rendering well. This is one area where I definitely preferred the 400mm F4.5 GM over the 600mm F6.3, as I felt the bokeh is smoother and transitions to defocus nicer on the 400mm.

At close distances the 400mm can completely compress away backgrounds, making them a lovely amount of cream.

In this seagull shot, the distant shore is visible but smoothly defocused.

I really love this dog portrait, however, where the transition from focus to defocus is really gorgeous.

This is an area where the quantity of bokeh can’t match that of the 400mm F2.8 GM, but the quality of the bokeh is certainly lovely.

Sony is using their Nano AR Coating II to help deter flare-related issues, and while lenses with this narrow of an angle-of-view are probably rarely going to be directed at the sun, I found that flare resistance was strong.

In short, this is an amazing optical instrument that just does a lot of things really, really well. Here’s a mini-gallery of more images for you to enjoy.

Conclusion

I think a lot of people are going to be shocked by the A) weight and B) price of the Sony FE 400mm F4.5 GM OSS. If you discounted the FE 400mm F2.8 GM by $10,000 it would still cost more than the 400mm F4.5 GM. I handed the lens to my wife after telling her that it was surprisingly lightweight, and after she hefted it for a moment, she asked, “How did they do that?” That’s a very good question, as Sony has definitely done some wizardry to product a lens that weighs over 400g less than Sigma’s 500mm F5.6. What’s more, this is a very, very good lens. It has beautiful optics that produces images that look like they came from a “great white”.

This should be an absolute favorite for those that are traveling on safari or another situation where they have to manage weight but still want exceptional image quality. I found carrying this lens remarkably simple for a lens that reaches out to 400mm with a relatively bright aperture.

Autofocus performance was impeccable, with the XD linear motors providing instant thrust and the algorithms doing their thing to make tracking effortless, regardless of subject. And the price (for such a lens) is really quite affordable, meaning that people who aspired to lenses like the 400mm F2.8 GM but find them distantly out of reach can get a lens that, if not quite as incredible, is certainly much more practical. In short, I think that Sony has crafted an absolute winner in the FE 400mm F4.5 GM OSS. I want one…

Pros:

Lightweight Design: At 994g, it’s significantly lighter than many competing telephoto lenses, enhancing portability.
TC Compatibility: Fully compatible with Sony’s 1.4x and 2x teleconverters, allowing for extended focal lengths without sacrificing autofocus performance.
Excellent Autofocus: Equipped with powerful XD (Xtreme Dynamic) linear motors for near-instant focus acquisition, even in challenging conditions. Maintains high performance with fast burst shooting and difficult backgrounds.
Outstanding Optical Quality: Consistently sharp images across the frame, delivering rich colors and minimal distortion.
User-Friendly Controls: Includes customizable function buttons and an easy-to-use manual focus ring, enhancing shooting flexibility.
Robust Weather Sealing: Designed with thorough weather sealing, making it suitable for outdoor use in various conditions.
Compact Size: Able to fit in standard camera bags easily, unlike heavier telephoto options.

Cons:

Not Arca-Compatible: The tripod collar requires an additional quick-release plate, which can be an inconvenience for those with Arca-Swiss style setups.
Limited Maximum Aperture: Though F4.5 is adequate for many scenarios, it cannot match the low-light performance of faster lenses (e.g., F2.8).
Small Focus Throw: The limited range for manual focus adjustments can hinder precision, particularly in critical situations.

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