Cameras are just Tools…
Think about those four words. If I were a sports shooter, who stared through the finder of a camera all day, or even for significant periods…I would actually likely not be shooting mirrorless. Same goes for portraits, weddings too really. I mean how hard is it to move a little AF box about? Why would you want to look at a TV screen all day? I love the OVF of DSLRs for weddings, portraits and deliberate shooting that can use the viewfinder. The reason I prefer ML, is when in astro or landscape mode, when it is traditional to use the back screen…ie essentially what a mirrorless camera is, a feed directly from the sensor, in finder or on the back LCD monitor. Everyone will have their use case, however it seems crazy to me to want to move away from an OVF for things like portraits and weddings; things that involve long staring and waiting for the shot through viewfinders (most tend to not use the LCD monitor and hold the camera at arms length). I personally think DSLRs are greatly suited to these tasks.
Okay, so why do You have a Z 8?
I spent a huge percentage of time in my recent years with cameras, almost exclusively using the live view function of DSLRs, or the LCD monitor as it is called on mirrorless cameras, barely touching the OVF. This is for landscape and astro work. I spend huge amounts of time in darkness, and the Z 8 ditches the old test shot routine at night as the monitor is so sensitive, I can compose in the dark and just shoot! I also gain a dual flip screen, which stops me laying on the freezing ground in winter to take vertical shots. I wanted to upgrade all my primes to a decent zoom, it made little sense to go with the old f mount zooms which are outclassed now, a couple of other factors - but the major being the way I used the camera. For portraits - heck, I still use the D800 and D810 cameras with their huge OVFs.
There is no huge difference in image quality with any of these cameras, from the D800, D810, D850, Z 8. There are some subtle differences and they should be considered by shooters who really push their files. You know who you are. So that means if you have a Dxx body think about the real reason you are upgrading. In fact, if you really are a image quality zealot as I am, the D850 is the best technical quality of all of these bodies…That said, in real life, compromise is always afoot, however I had many logical reasons to add the Z 8 into the mix for my shooting. However, when thinking of a tool to task camera, everything has pros and cons.
The biggest one I have found for the Z8 is the shutterless design means you can be gambling in LED lighting situations. Nikon has tried to mitigate the banding problems with fine tuning of the exposure time options and a photo flicker reduction mode etc but really, this isn’t a camera for weddings. I highly recommend making sure you have flicker reduction enabled in the menu of the Z8. This gives slight shutter lag but helps prevent banding. I have enough to think about on a wedding day without messing about fine tuning exposures to get banding under control, so I keep this mode enabled. I want no banding in any situation! Seriously, for wedding days and portraits… I'd just use dslrs. (They also work better with flashes). Don’t buy into the hype of mirrorless for those genres. Yes you can buy a z7ii or whatever in mirrorless land (which has a shutter and thus won’t have banding issues in certain light), however you’ll have much poorer battery life and will be essentially staring a TV screen all day whilst you focus and compose and relentlessly look for pictures. In my mind, this makes little sense and this is very different to the landscape genre whereby it is common practice to use the back screen more. Thus we were always using the monitor to make pictures: this was and is the way 99% of landscape shooters work.
Regarding the banding which can come about with shutterless mirrorless cameras…Case in point, upstairs in my home is full of LED lighting. The Z8 is a disaster when it comes to this; I cant focus on composing and shooting because ive got this crazy banding issue distracting me. However I can grab my d810 dslr and shoot at any shutter speed with zero problems. And best of all my battery will last all day (for weddings and portrait sessions and the like). Like I said…turn on flicker reduction in the Z8 menu and keep your eyes peeled.
Mirrorless Advantages
What you see is what you get view finder, with live histogram *
Eye AF and some other technical goodies which can for certain situations be a boon for certain shooters
Access to most modern lenses **
USB charging
Can technically have smaller full frame bodies (they aren’t much lighter or much smaller if you compare like for like however)
Video implementation and functionality is greatly improved over dslrs
Ibis
Potentially total silent shooting (sometimes ibis isn’t silent)
DSLR Advantages
The sensor is only on when taking the picture
Much better battery life
Optical Viewfinder
Better on and off camera speedlight flash support and AF assist beams work with red light
No issues with banding from LED lighting for any of the dslrs used as intended with the OVF - this is a big one if you shoot weddings / events / portraits. This is only an advantage when comparing to shutterless mirrorless designs though that are forced to use their electronic shutter
Build quality and ergonomics - especially if using the super magnesium based bodies such as the D810, D850
If you own one, you already own one - seem obvious, however…You just saved money and have some advantages to boot
Like mostly everything in life, there are pros and cons. This should be thought of in the context of your work, your shooting style, the way you do things. If you use your DSLR like a mirrorless camera - ie you are always on the back screen and are not taking advantage of the OVF, this along with other considerations may sway you to switch (or better add mirrorless, as I did).
* I have noted that people that know how to use a camera meter, do just about as well shooting with a DSLR in terms of obtaining a proper exposure, as they do on mirrorless. It is that simple. If they are messing up exposures on DSLRs, it shows more work is needed to understand the tool that they are using. What I tend to see is mirrorless doesn’t necessarily help - screen brightness throws them off as much as not understanding how metering works does. So whilst some might view this as some huge advantage, it is a weak one in my mind.
** Access to modern lenses may not be as important as it sounds, depending on the shooter. You might be perfectly happy with your lenses; newer is not always better.
Final Thoughts
I almost wish I did not ‘need’ to add a Z 8 into the mix. Why? I don’t like wasting money! However, I could not overlook how much easier using the Z 8 makes my life, especially when shooting at night. If you are content with what you use: be content. Only you know how you work and that should be the paramount concern. The final image on screen is all that matters. Most of the time the only obstacle to success is figuring out how to work out that thing about 2 inches behind the viewfinder…