Note sure if this will be of interest to anyone, but over the last couple of days I've shot with my Nikon Z9 (with the Nikon Z 100-400 S, and the 500mm PF), and today with my OM-1 with the 300mm F4 Pro. I may have mentioned some of these before but both cameras are superb image and video making tools, but as good as each is (and they are really good), there are a few things that one does better than the other ( I guess the same would apply to the OM-1 vs a Nikon Z8 ?) Some are minor and just annoyances, others more problematic and could maybe be solved via a firmware tweak (and no I'm not going to talk about size or weight of each system)?
OM-1 Advantages (in no particular order)
When using an external mic in the hotshoe (which is a lot of the time for me), on the OM-1 you only have to open a small cover on the side of the camera that's just for that port only. On the Z9 (and Z8), to get to the Mic port you have to open a much larger cover that also covers the headphone and (in the case of the Z9), the ethernet socket, leaving them exposed to the elements and potential water ingress in inclement weather ?
When flicking from Photo to Movie mode on the OM-1 (which I've assigned to the lever on the back of the camera next to the AF joystick, so it behaves much like the Nikon Z cameras), the OM-1 doesn't pull across the shooting settings you had in photo mode and vice-versa, but fully remembers what program mode, aperture, shutter speed etc you had dialled in for Movie mode making the two shooting modes completely independent of each other. So for example I could be in Shutter priority in photo mode shooting at 1/1600 sec at F4, and when I flick across to movie mode it remembers where I was last at say, manual mode, 1/100 sec f5.6. On the Z9 it just doesn't work that way and it continually bugs the hell out of me, that every time I flick into movie mode, I have to adjust all my settings again, then back again when going into movie mode.
The AF and AF subject tracking on both cameras is pretty amazing, but the OM-1 system is sooo much easier to use and it's a much simpler set up. With the Z9 there are many more AF modes and you really have to get to know them to get the best out of the camera. Overall I still find the OM-1 AF more responsive that the Z9 (albeit not be a huge margin), and seems to find and hold onto a subject more tenaciously than the Z9, and initial acquisition is certainly quicker on the OM-1
I like having a proper mode dial on the OM-1 vs pressing a button and then turning the sub command dial on the Z9, so choose between P, A, S, M for example.
Much prefer the implementation of the OM-1's memory banks that are stored in C1-C4 on the mode dial, rather than the setting banks on the Z9. Never really liked the setting banks on my Nikon DSLR's but Nikon seems to be sticking with this for their pro-camera bodies.
Still amazes me that despite many companies now including their version of pro-capture in their camera bodies, than most don't allow Raw files and don't give any like the options that the Olympus bodies give you.
The IBIS on the OM-1 is still the standard by which others will be judged. I'm constantly amazed that I can hand hold a 300mm lens (600mm equivalent),reliably down to 1/2 second of more if required.
OM-1 can shoot frame rates fast than 20fps (for example 50fps in pro capture) and all rates are available in raw whereas anything over 20fps on the Nikon reverts to jpg only.
Z9 advantages (in no particular order)
No expensive shutter mechanisms to break and induce shutter shock (although to be fair (touch wood), I have to say all my Olympus bodies have been faultlessly reliable).
Amazing buffer if using the right CF Express Card and using the right raw file type in camera pretty much makes the buffer endless (or until the card fills).
I like the fact that when in movie mode, whether you are shooting in 8 bit or 10 bit mode, you still have access to ALL the picture profiles, whereas on the OM-1 in 10 bit mode you only have the choice of OM Log 400 or HLG.
The sheer breath of video formats and frame rates on the Z9 is breath taking (4k 120p, 8k 60p all internally.
As good as the battery life on the OM-1 is (and it's very good), even with the grip and a second battery, the Z9 battery just goes on and on and on.......
Love the fact that when you are shooting or reviewing images in portrait mode, all the information in the viewfinder or rear screen adapts to the same aspect (think Nikon stole that from Fujifilm !)
The 45mp files from the Z9 are just lovely and still gives a D500 matching DX crop of 20mp.
Despite the lower resolution of the Z9's electronic viewfinder (3.5mp vs 5 in the OM-1), somehow the Z9's seems as detailed and is as close to a normal analogue viewfinder as I've seen and it's refresh rate never seems to drop even when light levels drop.
No system or camera body is perfect of course and that certainly goes for OM-Systems (Olympus) and Nikon (as well as others), but these really are two fantastic bodies with great lenses in both system. I think my takeaway in owning both, is will all the hoopla surrounding the new Nikon Z8 (which like the Z9 will surely be an amazing camera), micro four thirds users shouldn't feel short changed or overly jealous, as the OM Systems (Olympus) system really can give the big full frame boys a run for their money. If I was asked what is my preferred rig over the two mentioned at the top of this post, honestly I'd have to say the OM-1 with the 300mm F4 Pro, except when light levels drop or I need to shoot video formats the Olympus can't offer. Do I really need a Z9 then - no, it's an expensive luxury and I'd be perfectly happy with just the OM1 system if i had to, but then sometimes it's nice to have some luxury's in life
Large red damselfly 1 by Alf Branch, on Flickr
Large red damselfly 2 by Alf Branch, on Flickr
My hubby likes to joke ‘is it too complicated for you?’
You have to keep your wits about you. 
Baby Grasshopper by Pete, on Flickr
Chrysis Ignita 1 by Alf Branch, on Flickr
Chrysis Ignita 2 by Alf Branch, on Flickr
red back by Alf Branch, on Flickr
Dicyrtomina saundersi by Alf Branch, on Flickr
Collembola stack by Alf Branch, on Flickr
