Nikon re-entered the mirrorless camera market (with the Z System) a few months after the exited it (with the Nikon 1). Instead of going for very small cameras with a very small crop sensor (1"), this time Nikon started with a pair of full frame models, which differed primarily only in the sensor used.
Since that re-introduction, we've gotten both original models updated, as well as many new models.
The Zf, Z5, Z6, and Z6 II use a 24mp full frame (FX) sensor, while the Z7, Z7 II, Z8, and Z9 use a 45mp full frame (FX) sensor. The Z30, Z50, and Zfc use a 20mp APS-C (DX) sensor. In many ways the current Z6 II/Z7 II combo slots almost exactly between the Nikon D750 and D850 DSLRs, with the Z6 II being very D750 like, the Z7 II being very D850 like. Indeed, the Z7 II and D850 share the same basic sensor design, while the Z6 II has a completely updated version of the sensor used in the far older D750 (and now also used in the D780 and Zf). The Z5 uses the older D750 sensor and is really something akin to a D610 in mirrorless form. The Z8 and Z9 use a stacked image sensor that allows them to drop the mechanical shutter and simplify the physical aspects of the camera. The APS-C (DX) triplets all share the same 20mp sensor used in the D7500 and D500, though updated with phase detect focus technology.
Note one thing: EXPEED 7 and all of its performance and autofocus improvements is currently only available on the Zf, Z8, and Z9. Those three cameras are the preferred Z-mount cameras at the moment.
Choosing between the Z6 and Z7 level is relatively easy. The only differences between the cameras (originals or II models) are:
- Resolution / Size: 24MP (Z6) vs. 46.5MP (Z7). The Z6 models will have less resolution, but smaller files.
- AA Filter vs. None: The Z6 models will have micro-blur for less moire due its AA filter.
- Speed: 12 FPS vs. 9 FPS (now 14 FPS versus 10 FPS in the IIs). The Z6 models will operate at faster frame rates.
- 12-bit raw buffer: 36 vs. 24 (higher in the II models). The Z6 models can take more continuous images without stopping.
- Video: Oversampled 4K vs. Sub-sampled. The Z6 models will have better video.
- Price: $2000 vs. $3400. The Z6 models are less expensive.
- AF Points: 273 vs 493. The Z6 models have larger AF points.
- Base ISO: 100 vs. 64. The Z7 models will be better at low ISO.
- ISO at Dual Gain point: 800 vs 400. The Z6 models tend to be better at higher ISO values.
- 14-bit raw sensor readout: 1/22 vs. 1/16. The Z6 models will exhibit less rolling shutter.
At 24mp full frame, the Z5 versus Z6, Z6 II, or Zf produces a different set of differences to look at:
- Sensor: the Z5 is the older D750 sensor updated for mirrorless, while the Z6 models and Zf use a newer generation sensor. The Z6 and Zf models have dual gain technology, the Z5 doesn't. The Zf has EXPEED7, the Z6 II doesn't.
- Speed: the Z5 maxes out at 5 fps, while the Z6 and Zf models have faster options.
- Cards: the Z5 uses SD cards, while the Z6 uses XQD/CFe, the Z6 II uses both XQD/CFe and SD, while the Zf uses both SD and microSD cards.
- Video: the Z5 uses crop for 4K video while the others don't.
And in DX (APS-C), the triplets are basically the same camera internally and produce identical image quality, but:
- Z30: no EVF and the control UX is designed for vlogging.
- Z50: the first-born is a solid DSLR-like camera lacking mostly USB charging.
- Zfc: basically the Z50 II but designed with a different control UX that mimics the old Nikon film SLRs.
Finally, we have the flagship Z9 and it's smaller brother Z8, both of which couple a stacked Z7 II type image sensor with the Nikon D6 DSLRs feature and performance set and EXPEED7's new autofocus capabilities.
The focus performance of the full frame Z cameras other than the Zf, Z8, and Z9 is not quite D6-generation DSLR in level, but higher than many older Nikon DSLRs, particularly with the II models. It takes some adjustment for a Nikon DSLR user to get the full performance that the Z5/Z6/Z6 II/Z7 II is capable of, which led to a lot of focus complaints in early hands-on testing. Not so with the Zf, Z8, and Z9, which arguably have the best focus systems of any current competitive mirrorless cameras.
All the FX bodies are feature rich, including advanced features such as focus stacking, multiple exposure, time-lapse, and more (indeed, it takes me over a 1000 pages to fully do justice to these cameras in my Z5, Z6/Z7, Z6 II/Z7 II, Z8, and Z9 books).
Meanwhile, I'd say that the Z50 slots somewhere between the D5600 and D7500 DSLR models. Reduced performance from the full frame cameras, but not badly reduced.
In terms of lenses, for full frame we now have plenty of key lenses (with more due by the end of 2022):
- Primes — f/1.8 lenses at 20mm 24mm, 35mm, 50mm, 85mm, and 135mm. These lenses are better than any other prime at those focal lengths Nikon has produced in the past. These are very high quality lenses. f/1.2 lenses are available at the 50mm and 85mm focal lengths (35mm coming). Plus we have f/2 and f/2.8 compact primes at 26mm, 28mm, 40mm, and 50mm (macro). A solid start with primes, and one that should continue to get filled in as time progresses.
- Zooms — Two basic sets were originally developed: the f/2.8 set at 14-24mm, 24-70mm, 28-75mm, and 70-200mm, and the partial set of 14-30mm f/4, 24-70mm f/4, and 24-120mm. A second f/2.8 set was produced at 17-28mm, 28-75mm, and 70-180mm, without all the S-line bells and whistles. I'm going to sound like a broken record: all these zooms are at least as good, if not better, than any equivalent Nikon has produced in the past. The 24-70mm f/4 may be the best kit lens you can buy for a full frame camera. Plus now we have the 100-400mm f/4.5-5.6 and 180-600mm f/5.6-6.3, both of which are as good a variable aperture telephoto zoom as you'll find.
- Exotics — It took a little while for them to start showing up, but today we have the svelte 400mm f/4.5, 600mm f/6.3, and 800mm f/6.3 PF, plus the flexible-but-expensive 400mm f/2.8 TC and 600mm f/4 TC. All are winners optically.
For crop sensor cameras, lenses are sparse:
- DX — 12-28mm f/3.5-5.6 PZ, 16-50mm f/3.5-6.3, 18-140mm f/3.5-6.3, and 50-250mm f/4.5-6.3 zooms. We also have a 24mm f/1.7 prime. Fortunately, the zooms all have VR built-in (the DX cameras don't have sensor-based VR like the FX cameras do). The 16-50mm is the best compact kit zoom from any maker, while the other zooms are just very good to excellent.
Nikon wasn't kidding when they said that the mount changes freed up their optical designers to create better lenses.
Unlike Canon RF when it was launched, the Nikkor Z lenses did match up very well with the bodies from day one. The Z6 and Z7 are high consumer, prosumer cameras, and the Z lenses tended to be priced and perform at an even slightly higher level.