The Fujifilm medium format titan was already called into question by many because 100 megapixels is overkill for most photographers. Well, Fujifilm didn't just double-down on that, they used a Pixel Shift mode to quadruple-down.
I've already waxed lyrical about the Fujifilm GFX 100 this month, singing how it's even more impressive than you might have realized once you see inside the specialized factory which makes it. Well, I'm going off again, this time over the Pixel Shift mode that was added through a firmware update.
My first experience with Pixel Shift was with a much smaller sensor: the Olympus OM-D E-M1 Mark III which uses a micro four-thirds sensor. I was thoroughly impressed that, handheld, I could take pictures of most subjects — even wildlife — and increase the image resolution far beyond the sensor's maximum. If you're not sure how that's achieved, I implore you to Google it as it's a little time-consuming to explain, albeit rather straightforward.
Well, Fujifilm updated the GFX 100 to include this technology, increasing the maximum image resolution from 100 megapixels, to 400 megapixels. I'll echo what I said in the first line: 100 megapixels is overkill for most photographers. Even in my niche work macro stacking watches for commercial use wouldn't see much use out of 100 megapixels over, say, just 50 ("just.") So, 400 megapixels really will take some spectacularly specific work to see any form of a necessity for it. That doesn't mean, however, it isn't incredibly impressive. I shot an image from a Tokyo rooftop in daylight with the GFX 100 just to see how much I could zoom. A 200% crop on a baseball field showed the players clearly — players I couldn't really see when viewing the full image. Well, with 400 megapixels, I could probably tell you their eye color.
A quick word of warning, though: you're going to need a computer with a high spec for these files not to cause your RAM, processor, and graphics card to fuse together in a smoldering blob at the bottom of your case.