Sony A1 or Sony A7R IV? If you Need the A1 Features, It’s Easy, otherwise it’s gear lust?
Related: EVF, gear, Roy P, Sony, Sony A1, Sony A7R, Sony A7R II, Sony A7R III, Sony A7R IV, Sony mirrorless
My recommendation to most photographers who don’t shoot sports/wildlife or 8K video is to save the $3500 and angle towards the Sony A7R IV—less than half the price of the Sony A1.
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Roy P writes:
I don't use the Sony A1 for landscapes, so it will basically be my one Sony camera for pretty much all other kinds of photography.
As for comparing the A1 to the A7R IV, I don't think it's a comparison at all. The A1 makes sense only if you are into action, sports, wildlife and people, as in events, and occasionally cityscapes / landscapes. If my primary use case is landscapes or macro, I'd stay with the A7R IV, unless the A1 gave me a compelling reason like increased dynamic range.
For landscapes, I suspect there will be a Sony A7R V which would have things like automated focus stepping for focus stacking, frame averaging and a Panasonic S1R-like multi-shot high-res mode enabled by a custom processor with motion estimation, etc. It might even have an 80 or 100 MP sensor.
Sony A1 System and Accessories 
So if you're planning to invest in an A1, considering landscapes is a very big if not dominant part of your work, you may want to think about an inevitable A7R V, rather than the A1, and stay with the A7R IV for now. Or make the GFX 100S your landscape workhorse, in which case an A7R V becomes irrelevant. Regardless, a very big part of the cost of the A1 comes from its super high frame rate, large buffers, etc., which make sense only for action and sports. If your primary use case is not action photography, then you would be needlessly paying a huge premium for the A1.
BTW, the new user interface in the A1, while not perfect, is an improvement over the UI in the A7R IV, A9, etc. I quite enjoyed using it in the A7S III. The Olympus EMDX1 – jeeze, it will take me a while to remember what its name is! – has a similar UI. The UI by itself is not worth an upgrade over the A7R IV, but the EVF is excellent. And the AF tracking is just excellent.
The human / animal / bird eye AF all remains to be seen. Tony Northrup claims the Canon EOS R5 is even better at bird eye AF. I saw your question about eye AF being really iris AF and not eyelash AF or eye glasses AF. That also remains to be seen. My guess is, over time, with AI/ML, that will improve, and it’s potentially improvable in firmware.
DIGLLOYD: the financial difficulty of paying for a second expensive camera* aside, my uses for a Sony mirrorless camaera body are already well served by the Sony A7R IV.
Whether I’d go for an A1 depends on how the A1 feels operationally, and whether it can improve my shooting somehow. The awesome EVF might be one such point (focus accuracy) as well as just enjoyment. Blackout-free shooting, faster focus tracking and 8K video are all terrific, but but have little value for landscape stills shooting.
Most important of all: can the A1 serve my purposes for lens evaluations at least as well as the A7R IV (50 vs 60 megapixels shouldn’t matter). For example, the Sony A1 must not have PDAF banding as with the Sony A9 (I don’t know if the A9 II solved that). The A7R IV has no such issues, but with the A1 clearly aimed at high-speeds shooting, the wrong answer could make the A1 DOA as a general purpose camera.
So the Sony A1 has to at least sum up to a "no losses" and “all wins” on the features—no downsides, price aside. And then that has to be set against the possibility of a Sony A7R V later this year, which could have that awesome EVF, lossless-compressed raw support, and various other improvements. But I am dubious that we will see support for focus stacking, frame averaging and a Panasonic S1R-like multi-shot high-res mode in an A7R V. And the first two of those could be done witih a firmware update.
* On top of the Fujifilm GFX100S and at least one lens.
