Nikon Z6

13. Autofocus Performance

Although the Nikon Z6 sports a completely new 273-point autofocus system, it shares a lot of focusing DNA with Nikon’s DSLRs when used in live view. That is not necessarily a good thing. Nikon DSLRs, especially the newest models, are known for their high-quality phase detect autofocus systems when shooting via the viewfinder. But Nikon’s live view autofocus performance, even on the company’s best DSLRs, is really just so-so.

Although the Z6’s autofocus does draw inspiration from Nikon’s traditional viewfinder autofocus as well, it definitely is closer to that of Nikon’s live view focusing system. The good news is that the addition of on-sensor phase detect pixels lets the Z6 focus quite quickly, and other features like Low-Light AF are better than Nikon’s previous live view attempts. If you are using AF-S mode for single-servo autofocus, the Z6 has an amazing autofocus system that will not disappoint (as explained more in a moment).

The bad news is that the Z6 focus system is not as robust as some other mirrorless cameras on the market. For tracking subjects, it isn’t at the same level as the 153-point phase detect system found in the Nikon D5, D850, and D500, or even the 51-point system found in older Nikon DSLRs like the D750. You’ll also find the DSLR autofocus layout and options to be much more extensive and logical, while the Z6 includes some peculiar handling choices in this respect.

For instance, here is a comparison between the autofocus area mode options on the Nikon D850 and Nikon Z6:

As you can see, the D850 clearly comes out ahead. The Z6 doesn’t have D25, D72, or D153 dynamic-area AF points. Nor does it have Group Area AF. And although both cameras have 3D tracking, its implementation – as discussed in a moment – is more awkward to use than that of the D850, hidden under the Auto Area AF mode rather than as a separate option of its own.

13.1 Ergonomics

The Nikon Z6 doesn’t have a dedicated button to change autofocus settings. This is a departure from Nikon’s classic design choice, to have an AF-M switch on the front of the camera with an autofocus button inside. In its place, Nikon expects you to use the quick menu – accessed via the “i” button – to change focusing settings, or otherwise assign a custom button for that purpose.

Personally, I’ve chosen to assign my movie record button to change autofocus settings, and it’s not a bad solution. Press the button and spin one dial to change between AF-S, AF-C, and MF. Spinning the other dial changes autofocus  area modes: Auto Area, 9-Point Dynamic Area, Wide Area, Pinpoint (only in AF-S), and so on. Note that the Z6 does not have an AF-A mode to switch automatically between AF-S and AF-C, which is not a big deal for most of this camera’s users, but nonetheless matters to some photographers.

Once you assign autofocus settings to a good custom button, you’ll find that the Z6 works in much the same way as other Nikon cameras. Of course, that does prevent you from using the button for a different custom function, which isn’t ideal. As mentioned earlier, this takes away a spot to assign something like metering or bracketing. Still, if you change autofocus settings frequently, assigning a custom button is much better than entering the “i” menu all the time.

Lastly, note that you cannot use the Z6’s LCD touchscreen to control your autofocus point while looking through the viewfinder. Other mirrorless cameras have this capability, and some photographers have noted it to be a useful part of their shooting styles. Personally, I prefer the joystick instead, and I wouldn’t use the touchscreen for this purpose even if it were available. But if this is a feature you think you would use, just keep in mind that the Z6 doesn’t have it – at least at the moment. A firmware update could conceivably add this capability.

13.2 AF-S Performance (Static Subjects)

The Z6’s autofocus is superb for static subjects, focusing quickly and accurately, including in low-light conditions. You’ll still want to find a subject with good texture, though, not just a single sharp line or soft transition. And, as covered more in a moment, you get the best performance using native Z lenses rather than F-mount lenses via the FTZ adapter.

With the native Nikon Z lenses, the Z6’s AF-S (single servo autofocus) is simply excellent and very accurate. In fact, when compared to DSLR performance, the AF-S focusing performance of the Nikon Z6 is superior for a number of reasons:

First, unlike DSLR cameras that have a separate phase-detection autofocus system that does not always match the lens, mirrorless cameras focus right on the sensor plane. This basically eliminates focus variances between the camera body and the lens and removes the need for fine-tuning lenses.

Second, unlike DSLR cameras that require lenses to always focus at their widest apertures (to keep the viewfinder bright and to allow maximum light to reach the phase detection system), which results in focus shift issues, the Nikon Z6 stops the lens down to the exact aperture before it focuses, which pretty much eliminates focus shift. Note that the Z6 only stops down to focus from maximum aperture to f/5.6. When using smaller apertures like f/8-f/22, the camera keeps the lens locked at large enough aperture to pass sufficient light to the sensor, then stops the lens down to the desired aperture right before the image is captured. This is a very smart way of mitigating focus shift on the Z6, which drastically reduces focusing issues.

Lastly, I found the Nikon Z6 to focus extremely accurately on a high-contrast test target when using Imatest software – enough so that it matched our best possible manual focus efforts in nearly every case. This is a big deal when testing lenses; the Z6 is pretty much “dead on” every single time.

Overall, autofocus speed and accuracy are quite impressive, with practically no hunting for focus at all under most conditions. You have several autofocus area modes to choose from for AF-S, including a “Pinpoint” area mode previously found only on the D850 in live view. This is a great way to set an extremely small focusing box to lock onto a very precise subject. It takes a bit more time to autofocus when you use this method, so I personally prefer the slightly larger area mode by default, but this is a nice way to make sure that you are targeting your exact subject – for example, the center of a flower rather than its petals.

One missing feature on the Z6 at the moment is the lack of “Eye AF” – the ability to prioritize focus on a person’s eye, not just their face in general. This applies both to AF-S and AF-C, and it is a very useful feature. However, Nikon has already announced that Eye AF will arrive in a firmware update for the Z6 in May, so it is only a temporary issue. Props to Nikon for releasing firmware updates that add genuine features to the Z6 and Z7 rather than just fixing bugs.

So, all things considered, the Z6 is an excellent camera for photographing stationary subjects. Especially if you already prefer shooting in live view, such as many architectural and landscape photographers, you’ll find the Z6’s AF-S to beat almost any other option on the market for focusing on a non-moving scene. It’s fast and accurate, and it has enough options to make autofocus easy even in tricky conditions.

13.3 AF-C Performance (Moving Subjects)

Although the Z6 does a great job at single-servo autofocus, continuous autofocus is more of a mixed bag. That’s especially true when you try to track your subject across the frame. Although it does a better job locking onto and following your subject than Nikon DSLRs in live view, it is far from perfect and frequently misses focus in a series of AF-C images. Note that it is hardly the worst tracking performance for a mirrorless camera, and you definitely can get good photos shooting AF-C, but it still lags behind DSLRs significantly.

That’s especially true in dark conditions, since the low-light AF simply doesn’t engage in AF-C mode (and even if it did, it wouldn’t be nearly fast enough to keep up with a moving subject). You’ll need to switch back to AF-S if you want any chance of the camera locking on in dark environments.

Previous Nikon users might find another thing odd: In AF-C mode, the red box that indicates proper focus never turns green, even when the photo is completely sharp. Instead, it stays red and unchanging the entire time, unless the Z6 has completely failed to find focus, at which point the box starts blinking. Although this isn’t unworkable behavior, it’s a bit disconcerting if you’ve internalized that red means out of focus and green means tack-sharp.

Even weirder, though, is the way to lock onto a subject and track it across the frame. On Nikon DSLRs, this is known as 3D Tracking; on the Z6, it’s accessed under “Auto-Area AF” instead. Once you’re in Auto-Area, you need to press the center “Ok” button in order to bring up a box to position over your subject. Move it around and press Ok again, or start focusing (either by half-pressing the shutter button or by pressing AF-On), and the Z6 will lock onto that subject and follow it around. To change subjects, you need to press the Ok button another time, which will reset the box to the center of your frame and begin the whole process again.

Sounds confusing? It is. In practice, even though it doesn’t take long to internalize the setup process, the whole thing never quite stops being awkward. Keep in mind, too, that this is the only way to track your subject across more than just nine focusing points. So, it’s likely something that most photographers will use at some point.

On balance, the Z6 has some major flaws for tracking subjects and using AF-C mode in general. It can work, of course, which is why we’ve seen so many successful wildlife photos taken from the Z6 and Z7 already. But that doesn’t mean it is optimal, or that it will track your subject at the level we’ve come to expect from Nikon’s top-of-the-line DSLRs. I would argue that the Z6’s autofocus tracking is about on par with that of the older 39-point autofocus system for DSLRs, found in cameras like the Nikon D5600, D610, and Df.

13.4 Low-Light AF

The new “low light AF” feature on the Z6 uses longer shutter speeds to gather more light, creating a brighter image preview in order to help the autofocus system lock on in dark environments. The downside is that it can take quite a bit of time to focus when using the low-light AF feature, and the image preview becomes quite laggy as a result of the longer shutter speeds. To me, those downsides don’t matter too much, because the low-light AF feature lets the Z6 shoot in much darker conditions than would otherwise be possible.

The Z6 focuses best on high-texture areas, so make sure to find subjects with as much contrast as possible when you want to use this feature. If you find a good subject, you’ll be able to use the Z6 in remarkably dark conditions to lock focus precisely. I took the photo below in very low light environment and the camera was able to autofocus on the rocks without any issues:

In fact, I like the brighter preview so much that I wish you could use it while focusing manually, particularly for something like Milky Way photography. As good as the Z6’s low-light AF can be, it still won’t autofocus on a star in the dark of night. That’s no surprise, of course; I wouldn’t expect such insane performance, even though the Fuji X-T3 somehow manages to make it work. But I would love to have the brighter preview available for manual focus work, since it’s not easy to pinpoint a star at night based on the normal LCD image. This, too, could be added with a firmware update, and it would be a very welcome sight.

13.5 Adapted Lenses via FTZ

When adapting F-mount lenses onto the Z6 via the FTZ adapter, focus performance noticeably declines. For one, low-light AF doesn’t work as well, so you’re confined to brighter shooting conditions. You’ll also find that the Z6 gives up focus more quickly in general, regardless of lighting conditions. You need to be more careful about your subject and find something with as much contrast as possible. Accuracy stays quite high when it does lock on, though.

It’s not actively bad, and it certainly succeeds more than it fails, but at the same time you can tell that the Z6 was made for native lenses. Even the speed of focusing is slower with the FTZ adapter compared to the fly-by-wire system in Z lenses. That won’t be as big of a problem when more Z lenses are available, but at the moment there isn’t even a native lens more than 70mm for the Z6 (and the only telephoto on their roadmap beyond 85mm is a 70-200mm f/2.8). So, if you’re eager to make the Z6 your main camera system, you better be willing to accept the somewhat worse focusing performance with the FTZ adapter.

Again, I’ll emphasize that these issues are not going to ruin your day-to-day photography. The autofocus performance from the FTZ adapter is not vastly worse; it’s just a step down. You can still get plenty of good photos from adapted lenses, generally without focusing issues at all. But if you tend to push against the boundaries of the Z6’s focus system anyway, you’ll run into them sooner when you adapt a lens.

13.6 Is the Z6’s Autofocus Good Enough?

Let’s say you’re a D750 shooter, and a group of Nikon engineers offers to build you a better version of live view autofocus. It’s noticeably faster, adds some extra tracking options, and works in lower light than before. But these improvements come at a cost: the only way to implement the new version of live view is to scrap the old, highly praised viewfinder autofocus system completely. For better or worse, both in live view and the viewfinder, you’re stuck with the new focusing system. Would you make the swap? Because that’s about where the Z6 is.

It’s not a scenario that many photographers would openly embrace, although I’ll caution that it’s not as bad as you might think. After all, a significant number of landscape and architectural photographers are using live view for most photos anyway. With this change, your live view autofocus system is more responsive overall, and it works better in low light conditions. Essentially, you are trading top-notch autofocus performance across the board for even better AF-S performance than you already had. Perhaps that’s more important to you than the advantages of the old viewfinder autofocus system. And, similarly, video shooters should welcome the better tracking for moving subjects, improving the camera’s usability by a significant degree.

Even if you’re a portrait or travel photographer, you might find that the new setup works just fine for your typical photography. That’s because, with some exceptions, you probably weren’t pushing the tracking and speed capabilities of your current autofocus system to its limits. Although you don’t gain much from this swap, you probably don’t lose anything critical to your everyday work.

It’s really the sports and wildlife photographers who should decline this offer outright. Nikon’s newest 153-point phase detection system – the one you’ll find on the D850, D5, and D500 – is excellent. It is perhaps the best autofocus system on the market today, and the older 51-point system in the D750 and other cameras isn’t much far behind. If you look at medium format cameras and laugh, knowing their focus systems would be useless for your fast-paced work, the Z6 probably isn’t the camera to you.

To sum it up, despite some flaws, the Nikon Z6’s autofocus is better than the live view system of any current Nikon DSLR. It works in lower light conditions and tracks subjects more smoothly, as well as nailing focus faster in the first place (particularly with native Z lenses). If you’re a live view shooter, you’ll like this camera a lot. And if you’re an AF-S shooter, this is arguably Nikon’s best system ever. But AF-C photographers who track subjects every day will want to look elsewhere on the market. Make your purchasing decision accordingly.

14. Shooting Speed (FPS) and Buffer

The Nikon Z6 is capable of shooting at up to 12 frames per second, although that frame rate comes with some important limitations. You cannot shoot 14-bit RAW – only 12-bit – and exposure is locked to the first frame in your sequence. By shooting at 9 FPS, you gain back the ability to set 14-bit RAW. But it isn’t until you’re down to 5.5 FPS that you get back Auto Exposure after the first photo in your burst.

If you always shoot Manual, this AE limitation doesn’t matter anyway, since you won’t be using Auto Exposure in the first place. But if you like shooting in Aperture Priority, the lack of AE can be quite annoying. It depends upon the burst, but this can result in some blown-out highlights later in your series if you aren’t careful – say, you’re photographing a bird that flies in front of a bright cloud. Good news, though – Nikon has already said that their May 2019 firmware update will restore AE ability at all frame rates. So, this is only a temporary issue (although nothing has been stated yet about 14-bit RAW at maximum FPS).

Overall, 12 FPS, even with limitations, is pretty impressive for any camera today. Each 12-bit lossless compressed RAW file is around 22.5 megabytes; that’s a lot of data to process. Unfortunately, though, the Z6 buffer doesn’t do a great job keeping up with all this information. You’ll only get about 35 photos at 12 FPS shooting, or roughly three seconds before the camera slows down. At 9 FPS and 14-bit RAW, that turns into 43 photos, which is almost five seconds of shooting. Here is the full chart, comparing the Z6 to the Z7, D850, D810, D800, and D750:

As you can see, the Z6 is solid in terms of overall buffer performance, beating the Z7 and roughly matching the D810 overall (a bit better or worse depending on file type). It is ahead of the Nikon D750 and behind the Nikon D850. Note that the Z6 does not lock up completely when the buffer fills; it continues firing individual bursts that range from 4-7 photos per second apiece (with an average of five FPS). This makes the Z6 very usable for continuous shooting.

One last thing to note is viewfinder blackout. Despite earlier reports to the contrary, the Z6 does not go completely dark when you shoot at fast frame rates. Instead, at 12 FPS, you’ll see a near-live preview of the scene, but with the viewfinder image only refreshed at 12 FPS. So, it’s jerky, but you’ll see the scene. At 9 FPS and slower, the viewfinder image will go black for a fraction of a second during individual frames, but the rest of the time will be live and quick to refresh – not too different from shooting with a DSLR when the mirror moves out of the way in mid burst. The key is that you need to turn ON “View all in continuous mode” in the Shooting/Display section of the Custom Setting Menu.