Coming from a background of wedding photography, mostly using available light (you're moving, subjects are moving, light is not always abundant) I really don't understand the obsession/overstatement of the shutter speeds required to handle various levels of detail.
IS is a nice feature; if you're using a camera that has it, you should use it where applicable. It does expand the range of subject illumination in which you can shoot hand held. But cameras without IS are still, absolutely, hand holdable. More here: https://phaseoneiq4.com/yes-you-can-hand-hold-150-megapixels/
Not to mention that not every shot requires/benefits from maxing out the resolution of every last pixel. There are many image quality reasons to shoot a given given camera other than resolution, such as dynamic range, color, tonality, lens look, sync speed, etc, do. So even if you're in a range where you're "only" getting 50mp worth of detail from a 150mp camera, that doesn't automatically preclude it's use to the creation of beautiful images (unless the specific shot you are doing is one where micro detail is a leading/major aesethic contributor).
That sounds about right, except for one critical argument: you don't really need a 150 MP camera for beautiful images, good colours, good dynamic range and leaf shutter lenses. If you're buying a 150 MP camera, the primary value proposition is the 150 MP. Otherwise, you do have lower MP count options, offering the exact same "aesthetic contributors" for a fraction of the cost.
And for wedding photography, 150 MP is overkill anyway.
I do need 150 MP for my large gallery prints (I would need a single shot 400 MP if one existed). So squeezing every single pixel of every camera I had is a critical requirement, for me. While a non-stabilised camera restricted my freedom of movement and creativity, tying me to a tripod in at least 50% of the situations, the IBIS allows me to access more creative angles, more difficult locations, more rapid light changing situations, while still realising the main value proposition of the camera I bought: currently, the 100 MP of the GFX 100. Even if pricing was identical (which is far from being the case) I would still have to choose as my 1st option the 100 MP stabilised camera vs the non stabilised 150 MP. The 150 MP would be my second option / camera, and I would consider it primarily for those extra MPs (leaf shutter lenses and tech lenses are another reason, but for my shooting they are maximum 20% of the shooting scenarios).
Simply because the GFX 100 allows me to focus more on creating images, than fiddling with my tools. It gets out of the way faster, like any good tool should. I've been on the "slowing down will make your shots better" path, and that while it may be true for beginning photographers who need to get out of the spay-and-pray mode of photography, for those of us who know what they need from their tools and their images, the IBIS-mirrorless-modern AF combination is really unlocking new creative possibilities. I would rather slow down to explore more angles, more fleeting light or movement scenarios, than slow down just because I need to focus on operating 3 metal legs and multiple knobs with all the paraphernalia associated with that. And even in those situations where I need to commit to doing that, I will do it primarily because those extra MPs count, because in my 1.80 by 1.20 to 3m by 2m gallery prints, every single bit of properly captured and processed detail counts.
It's hard to consider seriously the argument that even if you're spending the money for 150MP it shouldn't really matter if you're only getting 50MP out of that. The 10x price difference (German car level of investment) is hard to swallow based on "other aesthetic contributors" - especially when those same "contributors" can be realised with different tools for a fraction of the cost, especially considering the final display medium. While that argument may work for rich dentists and snobs, I wouldn't trust a real image creator making that argument. Sorry if I come across as harsh, but I spent too much time, energy and money feeding the marketing machines of camera makers and sellers, who kept convincing me that I always need more and more and more diminishing-returns-"special"-"magic'-"unquantifiable aesthetics"-gear, while in reality I only needed ... 400 MP stabilised single shots, which nobody can deliver (small laughing break allowed)
) And yes, while I'm in the target audience for that, I will really need 400 realised MPs not 50 MP with "added aesthetic benefits". So please, let's try a better sales pitch, next time
