Hands-on with Nikon’s new Z-mount lenses and FTZ adapter
Nikon’s new Z-mount marks a major departure for the company, which (barring the short-lived 1-Series) for almost 60 years has relied on the 1950s-era F-mount for its interchangeable lens cameras. The Z-mount is significantly wider than the older F standard, with a much shorter flange-back distance. As such, it provides Nikon’s optical engineers with greatly increased flexibility when it comes to lens design.
The new Z 7 and Z 6 are launching with three new lenses – the Nikkor Z 24-70 F4 S, Nikkor Z 50mm F1.8 S, and Nikkor Z 35mm F1.8 S, alongside an FTZ adapter for Nikon’s legacy F-mount lenses and a fourth native prime – the Nikkor 58mm F0.95 Noct – in development. Let’s take a closer look.
The Z-mount
The Z-mount is the widest 35mm standard lens mount in existence, at 55mm. Nikon claims that this enables lenses with maximum apertures as wide as 0.95 without significant vignetting, which means twice as much light as the F mount can allow. Because the Z-mount is designed from the ground up for mirrorless cameras, the interface is entirely electronic, and the flange-back distance is only 16mm: 2mm shorter than Sony’e E Mount.
This – plus the wide diameter of the lens throat – should make the Z-mount the most versatile lens mount on the market when it comes to adapting lenses from other systems – as well as potentially opening the door to high-quality, super-compact Z-mount wide-angle lenses in the future.
The wide throat should give Nikon’s designers and engineers plenty of flexibility, since it essentially moves the outer edges of the mount out of the sensor’s field-of-view. This should not only remove constraints on lens design but also allow plenty of room for sensor movement for image stabilization, for instance.
The 55mm diameter is, noticeably, the exact diameter of a 44 x 33mm medium format sensor, but that tight fit would end up re-imposing exactly the design constraints the Z-mount avoids.
FTZ adapter
There are a huge number of F-mount lenses in circulation, many in the hands of enthusiasts and professional photographers. As such, Nikon was very keen to maintain F-mount compatibility with the new Z 7 and Z 6. Enter the FTZ adapter: a weather-sealed and unusually smart mount converter, which offers full support for more than 90 of Nikon’s current F-mount lenses and partial support for more than 360. F-mount lenses with VR will benefit from the addition of roll correction, courtesy of the Z 7 and Z 6’s in-body stabilization system. Non-VR adapted lenses will receive 3-axis stabilization.
While the Z-mount is fully electronic, the FTZ includes a mechanical aperture actuator for older F-mount lenses that lack the current-generation all-electronic aperture interface. We haven’t had the chance to fully test performance yet, but our initial impressions of AF performance with adapted F-mount lenses are very positive. The FTZ adapter will ship in late September for $ 249 (you save $ 100 if you buy it with the Z 7 or Z 6).
Focus-by-wire design
Hybrid AF systems tend to work best with lenses that use single, light focusing elements, since it reduces inertia to allow a highly-precise contrast detection check. This, along with the need to focus silently for video work, encourages the use of different focus motors than the ones used for DSLR lenses.
A knock-on effect of this is that the Nikkor Z lenses don’t use the ring-type focus motors that Nikon has used for its high-end DSLR lenses. In turn this means designs with no physical connection between the focus ring and the focusing elements: an approach known as focus-by-wire.
Nikon uses this lack of mechanical connection by offering a speed-sensitive response: moving the focus a lot if you turn the ring quickly or in more subtle increments if you move it slowly. It’ll be unfamiliar if you’re used to DSLR lenses but it can allow fast and precise focus once you’re used to it. Nikon also let you use the focus ring for other functions, if you prefer.
However, this isn’t the only way focus-by-wire lenses can work, and there’s nothing to stop Nikon adding a linear response mode that would be more like the way its existing lenses operate. This is particularly useful for videographers, since it makes it possible to plan-out a focus pull, knowing that a 30 degree turn of the focus ring will give drive the focus to the distance you expect.
It would also be possible for Nikon to let you reverse the lens rings’ direction of operation, so that it focused like other brands’ lenses. At present, Nikon isn’t offering either of these options, but we’re hoping they’ll add them at some point in the future.
Nikkor Z 24-70 F4 S
The standard ‘kit’ lens for the Z 7 and Z 6 at launch, the Nikkor Z 24-70 F4 S is a lightweight constant-aperture zoom which features a buttonless retractable design, to save on overall size when the lens isn’t being used. Optical construction consists of 14 elements in 11 groups, including one aspherical ED (extra low dispersion) element and three regular aspheres. Nikon’s Nano Crystal coat is employed to reduce flare and ghosting, and a flourine coating on the exposed elements should make it easier to clean moisture and fingerprints from the glass.
Autofocus is driven by a stepping motor, and (in common with all of the new z-mount lenses) manual focus-by-wire is also available. The slim focus ring (Nikon calls it a ‘control ring’) can also be customized to allow control over aperture and exposure compensation.
Our initial optical impressions are that it is surprisingly sharp across the frame even wide open, but its bokeh suffers from onion rings and other patterns – which can lead to ‘busy bokeh – presumably due to the use of aspherical elements. This is not uncommon in new lens designs optimized for sharpness, and the amount to which it might be distracting is likely to vary from copy to copy of any particular lens.
Like all of the new Z-mount optics, the Nikkor Z 24-70 F4 S is a pretty lightweight lens at 500g, but feels well made. It features a minimum focus distance of 30cm (11.8 inches) and has 72mm filter threads. The 24-70mm F4 will ship alongside the Z 7 in September for $ 999.
Nikkor Z 50mm F1.8 S
Nikon is pretty proud of this one, and based on our early impressions, the company seems to have good reason. The Nikkor Z 50mm F1.8 S is an extremely sharp standard prime lens for the Z-mount, which Nikon claims has “nearly zero aberrations” when shot wide open at F1.8.
The 50mm F1.8 incorporates a nine-blade aperture, and optical construction consists of 12 elements in 9 groups, including two ED elements and two aspherical elements. Like the 24-70mm, the 50mm employs Nano Crystal coating to reduce flare and ghosting. Minimum focus is 40cm (15.7 inches). Autofocus performance seems broadly comparable to Nikon’s 50mm F1.4 AF-S. It’s positive (and almost completely silent), but not as snappy as some of Nikon’s ring motor-equipped fast-aperture lenses.
A subtle but very welcome addition to the lens hoods of the new Z-mount range (masked off in our shots of these early pre-production units) is a text panel which lists the lens with which the hood is compatible, and its filter thread.
The Nikkor Z 50mm F1.8 S will ship in late October for $ 599.
Nikkor Z 35mm F1.8 S
The Nikkor Z 35mm F1.8 S is a medium-wide prime lens, which looks extremely similar to the slightly larger 50mm F1.8. Comprised of 11 elements in nine groups, optical construction (again) includes Nano Crystal coating and like the 50mm F1.8, the 35mm features a nine-bladed aperture. It also shares the same 62mm filter thread. At 370g, the 35mm F1.8 is the lightest of the Z-mount lenses available at launch. Minimum focus is 25cm (9.8 inches).
Our initial optical impressions are positive: the lens is very sharp. However, there’s a significant amount of longitudinal chromatic aberration (pink and green fringing in front of and behind the focus plane, respectively), something Nikon prime shooters are undoubtedly already familiar with. Bokeh is generally pleasing, but there’s some patterning to out-of-focus highlights that aren’t very defocused, likely due to the use of aspherical elements. Autofocus is quiet, but sometimes felt slower than its AF-S counterpart, though this could be due to the beta firmware of the lens and camera.
The Nikkor Z 35mm F1.8 S will ship alongside the Z 7 in late September for $ 599.
Nikkor 58mm F0.95 Noct
We haven’t handled this one yet, but we can’t wait. Unveiled as a development announcement, Nikon claims that the forthcoming Nikkor 58mm F0.95 Noct will offer the “highest rendering performance” of all the first-generation Z-mount lenses, including “flawless” transitions between in and out of focus areas. A brand-new ‘ARNEO’ (‘AR’ for Anti-Reflective and Neo denoting ‘new’) coating will be employed to reduce flare and ghosting. An LCD panel will display aperture, depth-of-field and focal length information.
Lens roadmap
As well as the three lenses available at the point of launch and the announcement of the 58mm Noct, Nikon has also published a lens roadmap. This isn’t something Nikon has done before. Instead it’s a move taken from the Micro Four Thirds and Fujifilm X-mount playbooks: making clear to would-be buyers that the company will continue to expand the system and introduce the lenses you might one day need.
This makes sense because, for all its hundred-year heritage and more than 100 million F-mount lenses sold, this is a new system and would-be buyers will need all the reassurance they can get that it’s a system with a solid future.
Articles: Digital Photography Review (dpreview.com)
