Launched alongside a 600mm f/6.3 as one of two supertelephoto primes designed for “everyday shooting”, the Sony FE 400mm F4.5 GM OSS lens is the more affordable option – but it’s arguably also the more flexible of the duo, too. Its 400mm allows focal length you to get nicely close to subjects such as birds and wildlife, without being just that bit too close and finding it difficult to frame your subject. Its GM badge indicates that it should be one of the best Sony lenses.

　　Sony FE 400mm F4.5 GM OSS at a glance: $2700 / £2400 f/4.5 max aperture 2.5m closest focusing distance 994g Primarily designed as a full-frame lens – I’ve been using it with the Sony A7RV for my review – you can also use it with APS-C models as well, such as the Sony A6700. Equally, if you do need to get a bit closer with a full-frame camera, you can always shoot in APS-C mode. Being (relatively) lightweight, it’s designed to be used on the go without weighing you down too badly. Let’s see how it performs in the real world.

　　Features If you’re a wildlife or action photographer, a long telephoto prime lens may be high on your wishlist. A nicely long optic like this is great for photographing subjects such as birds, planes, cycling and so on. It’s also something you can conceivably use for portraits – providing you can get enough distance between you and the subject, to leave you with a nicely blurred background.

　　If that’s the kind of photography you’re into, it’s also fairly likely that you’ll want the best possible image quality, with sharpness and plenty of detail. As such, the fact that this 400mm is a G Master should be appealing, as it denotes that it’s Sony’s highest quality optic.

　　In terms of lens construction, this is a complex design which should deliver fantastic results. It consists of 22 elements in 16 groups, including one ED (extra-low dispersion) plus three Super ED elements designed to reduce chromatic aberrations. Additionally, it has an 11-blade circular aperture with optimised spherical aberration design in order to produce smooth and rounded background bokeh.

　　The closest focusing distance here is 2.5m. But as a lens that you’ll mainly be using for distant subjects, that’s more than fine.

　　Nano AR Coating II is included to suppress internal reflections which lead to flare and ghosting. The front element has a fluorine coating to protect against water, oil and fingerprints, while the lens is also fully weather and dust sealed for use in less than favourable conditions – exactly what you need from a lens designed to be used to photograph wildlife.

　　It can be helpful to use the camera on APS-C mode if you need to get a bit closer to the action, giving you 600mm equivalent – but bear in mind that your resolution will drop if you do so. An alternative way to get closer to the action is to use either a 1.4x and 2x teleconverter, giving you 560mm f/6.3 or 840mm f/9 equivalent reach when used with the 400mm lens.

　　The lens is equipped with Optical Steadyshot, which is designed to compensate for camera shake, and works in conjunction with the camera’s inbuilt image stabilisation system.

　　Build and Handling Sony’s new 400mm and 600mm lenses are the world’s lighest super-telephoto lenses in their class, being under 1kg each (excluding the tripod foot). The 400mm is lighter than Sony’s own competitors, including the FE 400mm F2.8 GM OSS, which is nearly 2kg heaver at 2,895g. It’s also lighter than the FE 100-400mm F4.5-5.6 GM OSS, which is nearly 50% more hefty at 1,395g.

　　Of course, there are benefits to those other lenses – including the wider aperture of the f/2.8 optic, and the greater flexibility of the zoom lens. But it’s extraordinary just how light the 400mm f/4.5 is to use. I walked around with it for several hours at a time and didn’t end up with a terrible backache, which has got to be a good thing.

　　What also helps is that the design has an optimised centre-of-gravity to make it feel more comfortable for shooting for lengthy periods of time, as well as when tracking or panning. I used it with the tripod foot attached to make it even more comfortable to hold, but it’s not an absolute necessity – especially if you want to keep the weight down to an absolute minimum.

　　The lens has quite a few rings, buttons and switches to take note of. There’s a manual focusing ring, which is the largest ring found on the lens. It has no hard stops, but it has a nice amount of give for when you’re trying to make small or precise changes. Manual focusing is not something I did with the lens a huge amount, but on occasion it came in useful.

　　Another ring, which is much smaller, acts as function ring. With this, there are only two settings which can be assigned to it – Power Focus and switching between APS-C/35mm. The former is manual focusing, but without the need to keep turning a focusing ring. It can be quite useful for quick changes, and without having to activate manual focusing with the switch on the side of the lens. It can also prove to be very helpful if you need to abruptly switch from distant to closer focusing (or vice versa), if a bird has just flown into a nearer spot between branches for example.

　　Alternatively, being able to swiftly move between APS-C/35mm is also quite useful if you’re photographing subjects which are just a smidge out of reach and want to quickly get closer.

　　A final ring houses four buttons which can all be used for Focus Hold, in other words to to lock focus on a specific spot without refocusing. Again, this is very useful for bird and wildlife photography where you’re anticipating the subject is going to appear in a specific location.

　　There are five switches towards the mount end of the lens. Some are fairly self-explanatory, like AF/MF, but you’ve also got Full Time DMF On/Off – you’ll need this set to On if you want to use the Focus Hold buttons to override autofocus and use manual focus. Then there is a switch for moving between the full focus range and 7m-infinity – this is very useful if you want to avoid the lens attempting to focus on something which is closer to you than the subject you’re trying to photograph.

　　The OSS switch is for switching on or off the optical image stabilisation, while finally you have a Mode 123 switch, for choosing between the different types of stabilisation, with 1 being the standard / all-purpose mode, 2 being used for panning shots, and 3 for when you want to keep up with erratic, fast-moving subjects.

　　A nice big lens hood comes in the box, which I find is useful for making sure rain and other contaminants don’t get at the front of the lens. It can be reversed when you’re not using the lens to keep size down for fitting more readily into your bag.

　　Autofocus This lens features two high-thrust XD linear motors, which are designed to deliver fast and precise autofocus. If you’re using it with a high-end camera such as the A9 III, it promises to focus track at up to 120fps. Although I was using it with an A7R V, which is not necessarily what you’d choose for wildlife and action type photography, it was still able to keep up with moving subjects very well indeed.

　　I switched on Sony’s Real-time Tracking with Eye Autofocus, setting it to eye-AF and found it nailed it with most subjects almost all of the time. In slightly lower light conditions, or where the subject was very far away it struggled a little more, but overall I was very impressed.

　　On top of that, it was also impressively quiet and quick, making it good for photographing wildlife. You do still have to get relatively close with a 400mm if you want to fill the frame, and something quiet like this helps to ensure birds and other nervous creatures aren’t too spooked by your presence.

　　Image Quality As I would of course expect from a Sony G Master lens with a high price tag, the FE 400mm F4.5 GM OSS is capable of producing some absolutely beautiful results. There’s a lovely amount of sharpness in detail across the frame, and at different aperture settings.

　　You’ll probably get the absolute sharpest results dropping down a little to f/5.6, but I was more than happy with the results that I got at f/4.5 in pretty much every situation.

　　The 11-blade aperture produces some fantastic results. If you happen to have some catchlights in the background of your shot, then you can get some lovely circular bokeh. This makes for some lovely images of birds in trees, but it can also be useful for portrait photography too – and I can imagine events or wedding photographers finding a use for this reason too.

　　I struggled to find any instances of chromatic aberration in my sample images, even when there were very high contrast areas in a scene, so those coatings are doing a great job. Indeed, if you’re only looking at your JPEG files, problems such as chromatic aberration, distortion and vignetting are automatically corrected so you won’t see any of it.

　　In raw files, if you’re using Adobe then its raw processing will remove these kind of problems too. You could disable shading compensation in camera if you really felt so inclined, but with reasonably narrow maximum aperture, it’s not likely to be a big issue either way.

　　Looking at uncorrected raws you can also see some visible pincushion distortion, but for the typical subjects you’ll be photographing with a lens like this, it’s unlikely to be a problem.

　　Sony FE 400mm F4.5 GM OSS: Our Verdict If you’re in the market for a supertelephoto lens for your Sony camera, then this is a fantastic option. Probably the thing I liked best about it was how relatively lightweight it is – shooting handheld is more than just possible, it’s eminently sensible in order to keep up with the subjects you’re following. It’s comfortable to shoot like this and it doesn’t kill your back if you’re shooting with it for a few hours.

　　OK, the trade-off is a narrower aperture than you might otherwise like to have in an absolutely ideal world, but I think it’s worth it.

　　This is one of two Sony telephotos launched at the same time, the other being a 600mm lens. While I’m in no doubt that that is also an absolutely wonderful lens, I think the 400mm is more appealing for a couple of big reasons. First of all, it’s simply more versatile for a wider range of subjects. You could conceivably use it not just for nature and wildlife, but also for events, sports where you’re fairly close to the action, and even portraits. With a 600mm, I’ve often found I’m just that little bit too close and can’t quite get the framing I like.

　　Second of all there’s the price. I’m not claiming that the 400mm is a cheap lens, but it costs significantly less than the 600mm. making it a lot more affordable – especially if you consider that versatility giving you a lot more uses for your money.

　　Overall, this is a superb lens for Sony shooters, and it comes highly recommended.

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