Recently, it became official: the Nikon Z series cameras have almost entirely replaced my DSLR for in-studio work and portraiture. The D810 still lives for the outdoors – landscapes and wildlife in particular.

Having used the Z series for about 15 months now, the amazing haptics, seamless transition, and absolutely brilliant lenses clinched the deal. In fact, I consider the Z6 and Z7 two of the finest digital cameras (period) ever made and certainly near the top of the best MILCs. No one else has made a full-frame mirrorless camera with such an excellent design and seamless transition from the DSLR counterparts; not to mention the enormous lens library if you consider existing F-Mount lenses with the adapter. Canon succeeds on the latter front, but the EOS R was an underwhelming mess of design and features (I am very impressed with the 1DX Mark III, however, and the EOS R5 and R6 seem to have fixed the terrible ergonomics of the R).

*Taken with iPhone 8 in DNG via Lightroom Mobile, edited in ACR/PS*

So, having spent a good amount of time now with the Nikon Z6 and Z50*, I feel pretty comfortable discussing a few of the shortcomings and features I would like to see implemented in the next iteration(s). A fair number of these would also apply in general to most mirrorless cameras – be it features that exist in some cameras but inexplicably not in all, or features that don’t exist at all but should.

The recently-announced Z5 addresses one of these features (dual card slots), however it uses two SD slots – I would like to see either dual CFexpress or CFexpress + SD in the next generations.

*Most of these apply more to the Z6/Z7 but a number are (or could be) applicable to the Z50 as well.

Firmware Updatable

Linear manual focus modes for Z lenses* – this should be a standard option on all mirrorless cameras. Fly-by-wire manual focusing is already a nightmare without the haptic feedback of a helicoid – not to mention the lag and subsequent backlash in focusing precision. Plus, with the increasingly video-stills hybrid nature of cameras, there is no reason not to have this (Fuji does it). Spend five minutes trying to pull focus during a video with fly-by-wire lenses and you'll want to shatter the camera. And no, there isn’t any mirrorless camera with sufficient video AF-C. Even the cameras that can keep focus locked, the transitions are still very harsh and uncinematic (particularly when “racking” focus from near to far or far to near). Possible exception is Canon and their dual-pixel AF, but I haven’t used their EOS R cameras enough to testify one way or another. The EOS cinema cameras are great and the 1DX Mark III is likewise very impressive.

*For those who don’t know: most AF DSLR lenses (except some newer ones, e.g. Nikon’s AF-P) and manual focus lenses have focus rings that are coupled to built-in helicoids. This gives them linear, mechanical, repeatable focus, usually with hard stops at each end in the case of non-AF lenses. The focus ring on a focus-by-wire design is not mechanically linked to anything and isn’t linear – turn the ring slowly and it may take 300 degrees to cover the full range; give it a quick twist and it may do it in 25 degrees. Not to mention, due to the lack of physical coupling, there is always lag between when you initiate/stop focus and when the camera indicates that you have, making it impossible to tell when you’ve hit your mark - inevitably ending up in you overshooting the target. Focus-by-wire is undoubtedly superior for autofocus, but it is garbage for manual focusing without some user selectable adjustments in its behavior (like Fuji offers) or rackable linear focus modes with hard stops a la some Sony and Olympus lenses.
IBIS based pixel shift for full color sampling and high-resolution still-life / product / landscape (see: numerous cameras from Olympus, Sony, Pentax, Leica, Panasonic). Note: not sure if this is firmware updatable or would require hardware adjustments in the imaging or processing pipeline. Leica added it to the SL2 via firmware so my guess is Nikon could too.
IBIS based astro-tracer (Pentax K-1) Note: again, not sure if this is firmware updatable or not, but as above, I don’t see why not.
Rotate monitor/EVF info when shooting in portrait orientation (why everyone doesn’t do this is beyond me)
In-camera focus stacked output. The Z’s can already do focus bracketing (or "shift" in Nikon-speak) but an option for in-camera blending and output (e.g. Olympus) would be nice for those who would prefer to bypass the Photoshop step; the excellent JPEG output from these cameras makes this a worthwhile feature. Of course, it should also still save the individual raw files.
Live Exposure modes: Olympus calls these Live Composite and Live Bulb. They may be proprietary, though the iPhone has a similar feature as may other cameras. Essentially, each mode allows you to see the image “develop” without waiting for the exposure to end (meaning you can end the exposure once it’s exposed to your liking). Live Composite shoots a series of consecutive frames and blends them into a pseudo-long exposure. Live Bulb is like a regular bulb mode, except the screen refreshes every so-many seconds (you set the frequency based on your exposure time as the sensor is only capable of 24 refreshes, I believe - e.g. a 48s exposure would refresh every two seconds).
Auto ETTR Metering Mode – auto expose to the right just until highlights clip. Think of it as an automatic exposure compensation mode. Highlight priority metering kind of does this, except in the reverse: it’s used to prevent highlight blowout by metering for the highlights (so, in a sense, applying a negative exposure comp). But in the case of ETTR, you want what the camera considers overexposure. Note that this is for RAW shooting only. JPEG shooters DO NOT want to ETTR.

Customizable thresholds for Auto EFCS. Currently this setting switches from EFC to mechanical at 1/320 (I believe), but it would be nice to have it simply switch over at 1/2000 or whatever speed you choose.
More flexible Auto-ISO thresholds. The "slow" to "fast" is decent (lowest appears to default to a little over 1/4x focal length), but more precise values – rather than ambiguous low-to-high steps – would be very nice. The Z50 is even less customizable than the FX cameras.
Allow non-CPU lens data selection to be assigned into the i-Menu. You can assign it to a function button, but not the quick access menu, which is senseless.
Add 21, 40, 75, and 90mm to the options in non-CPU data; they have 43mm and 86mm because once upon a time Nikon made a 43-86mm lens, but no 40mm or 90mm. Nikon: this is a mirrorless camera, people will be adapting all kinds of lenses. This could easily go for other focal lengths as well, these are just the ones I have noticed missing.
Proper shutter speeds in video mode to mimic shutter angle (e.g. 1/48th = 180°). As far as I’m concerned, just call it 180°, 172.8°, etc. when in video mode. The latter is both more consistent and easier coming from cinema cameras and eliminates the need to adjust shutter speed when changing your frame rate.
Fully separate the video and stills menus. In photo mode, you should see all photo-centric options in the menu and only those options. In video mode, you have only video-centric options. For the photo menu, just remove the video tab and a couple other options. For the video menu, redesign it entirely from scratch. For a camera that can output 12-bit RAW, a dedicated video only menu should be there. That, I feel, is one of the best possible changes to fully bring hybrid mirrorless cameras to maturity on the video front. When I’m shooting video on most of these types of cameras (whether Nikon, Canon, Panasonic, etc), I’m constantly frustrated by the cluttered menus and options and symbols that are entirely irrelevant to me (even if greyed out). A completely new video menu (think Blackmagic – easily the best videocentric menu interface out there in a camera under $5,000) would benefit stills and video shooters alike.
Z50 only – already implemented in Z6/7: option to use EVF only for shooting and the LCD for menu/image review. Currently our options are just EVF Only, Monitor Only, or Auto Switch.

Next Generation Additions/Changes

Dual Card Slots – while the choice to use the more robust XQD (and now CFexpress) format was a good one, and the single card slot doesn’t personally bother me, I would obviously prefer a second slot. No reason a UHS-II SD slot can’t fit in along with it, perhaps with a few millimeters of adjustment to the dimensions.
Internal 4K 10-bit 4:2:2 with N-Log gamma; leave HDMI output for the 12-bit ProRes RAW (though internal RAW video is not something I’d complain about – it would probably have to be Blackmagic RAW or similar, though, which is a superb format).
Sub-dial under the PASM (e.g. Fuji X-T3, X-H1, Panasonic S1/S1R) for either metering mode (my preference) or drive mode. Avoiding menu diving (even into the easily accessible i-Menu) as much as possible is preferable.
Mode dial should be permanently unlockable (e.g. Olympus). Push down to lock, push down again to unlock – we retain the option to leave it unlocked.

Electrical contacts for a vertical battery grip – the vertical grip Nikon finally released (sans any buttons or dials) was nothing but a joke at that price, and provided no controls. I don’t see the point in a vertical grip at all if you still have to awkwardly maneuver your hand to the regular controls to adjust settings and take a photo. I don’t even see how it helps with larger lenses.
FTZ adapter with Arca Swiss detachable tripod foot. I shouldn’t have to purchase two L-brackets (one for the camera, one for the adapter) because you decided to make a non-Arca Swiss non-removable tripod attachment. Fotodiox Pro and Metabones adapters are Arca compatible and removable. Or, if that’s too difficult, at least make one with no tripod mount - it can really get in the way when on a tripod.
Electronic front curtain at all shutter speeds (currently tops out at 1/2000). I assume this is a hardware limitation in the Z6/Z7 given that prior DSLR models had no such limit; it might be due to readout limitations at the faster speeds.
LCD that tilts in portrait orientation (e.g. numerous Fujis, Panasonic S1/S1R)
User selectable raw color – e.g. “Neutral Color” and “Nikon Color." This would work best if the Neutral mode was standardized across all manufacturers (pipe-dream). All companies have their own color and tonal adjustments baked into the raw files. Some kind of neutrality would make consistency much easier to achieve between different makes and models without having to jump through hoops in ACR or whatever you use. But, since that will never happen, I’d be happy with a simple “neutral color” mode that was standardized across all Nikon models (though tonal response, particularly at either end of the curve, will still vary from model to model based on the sensor architecture, processor, among many other factors). I’d love if my Z50 and D810 had the same color. Hasselblad is the only company I know of that does anything like this, with their “Natural Color Solution.”