Fujifilm has also included a touchscreen, but it has relatively limited functionality. You can set the focus point, select and change Q Menu items, swipe though images in playback, and double-tap on them to zoom in to inspect focus. It’s also possible to use swipe actions as virtual touch buttons; up shows a detailed RGB live histogram, down a precise dual-axis electronic level display, while left and right call up film simulation and white balance settings respectively. In movie mode, enabling Movie Optimised Control allows exposure settings to be changed silently using the touchscreen. But there’s no option to navigate and change menus by touch.

Fujifilm GFX100S: Viewfinder and screen

For the first time in its GFX range, Fujifilm has gone for the conventional SLR-style approach of using a fixed central electronic viewfinder, rather than a removable or corner-mounted unit. In many respects the camera is all the better for it; the design is less bulky than the GFX 50S, and the EVF doesn’t obstruct your view of the LCD screen when it’s tilted upwards for waist-level shooting, which is a problem on the GFX100. Compared to the GFX50R, the viewfinder protrudes slightly further from the back of the camera and has a noticeably larger eyecup.

Thanks to this extra hinge, the LCD can also be used for low level or overhead shots in portrait format.

Fujifilm GFX100S + GF 32-64mm F4 R LM WR at 42mm. 1/640sec at f/11, ISO 100. Eterna Bleach Bypass Film Simulation

Thankfully, there’s little to question about the GFX100S’s autofocus accuracy. Even with the 80mm f/1.7,  which is one of the system’s most demanding lenses in this respect, I found the camera was able to focus it consistently accurately, even when shooting off-centre subjects with the aperture wide open. When using eye detection, though, it had a certain habit of focusing on stray hair over the selected focus point, so it’s worth keeping an eye out for this when shooting portraits. Light levels have to drop extremely low before the system starts to struggle, too.

Fujifilm GFX100S: Performance

It’s not so long ago that medium-format digital cameras were slow and clunky beasts, but that’s no longer the case with Fujifilm’s cameras. In general, the GFX100S is just a responsive as any other modern mirrorless camera. With most lenses it powers up pretty much instantaneously when you flick the power switch, however the 80mm f/1.7 delays this by a second or two as it goes through a focus calibration routine. The camera responds instantly to all of the physical controls, but the touchscreen can be a little laggy. This didn’t really bother me, though, as I found little need to use it.

Overall, the only time when the camera feels genuinely slow is when it comes to playing back your shots. Even using a fast UHS-II SD card, it takes a second or two to render an image file after initially loading a low-resolution thumbnail. It’s also a little sluggish scrolling through and reviewing files. But this doesn’t seem entirely unreasonable, given the vast file sizes.

Operationally, the camera is impressively discreet. As on the GFX100, the mechanical shutter is extremely soft and well-damped, so you can happily shoot in quiet locations without being noticed. Set the shutter to its electronic front curtain mode and it’s particularly unobtrusive. Fujifilm’s LM lenses are extremely quiet focusing, too, although those without linear motors ones tend to be more audible.

In typical Fujifilm fashion, the automated systems all work very well. Metering is extremely reliable, so you’ll generally only have to override it for aesthetic effect, or if you want to protect small, bright highlight areas. The camera does an impressive job of matching the perceptual brightness of the scene, too, producing darker files when shooting at night.

Auto white balance is essentially faultless – with most cameras you can expect to improve upon the camera’s judgement in raw processing, but that’s very rarely the case here. This being Fujifilm, the in-camera colour rendition is excellent, too. It might seem ridiculous to talk about JPEG quality from a £5,500 camera, as most users will surely process their images from raw, but in many situations the GFX100S can deliver superb results direct from the camera.

Overall the image quality is, needless to say, astonishing. Fujifilm has worked extremely hard on making it as easy as possible to exploit the sensor’s resolution, with a low-shock shutter, effective in-body stabilisation and excellent lenses. You do still have to pay attention to your settings, of course; for example the 32-64mm f/4 zoom really needs to be stopped down to f/8 or smaller for best results. But in general it’s remarkably easy to get superb image files without having to set up a tripod, even in marginal light.

Get everything right and images simply ooze detail. Low ISO shots are entirely free from visible noise, with extremely impressive dynamic range in the raw files. This means it’s possible to expose to retain highlight detail and then pull up three or four stops of additional detail in the shadows in raw processing. With so many pixels to play with, a little noise isn’t going to do much harm anyway.

Fujifilm’s in-body stabilisation is extremely effective. With such a high-resolution sensor, any camera motion will be visible, and without IS you’d have to use shutter speeds a couple of stops faster than the old 1/focal length rule of thumb would have you believe. But with the GFX100S, I was able to get consistently sharp hand-held images at shutter speeds as slow as 1/5 sec when using the 32-64mm f/4 and 50mm f/3.5 lenses, and 1/10sec with the 80mm f/1.7. Combine this with the camera’s very decent high-ISO performance and you can shoot hand-held in very low light.

For those wondering just how much extra image quality you can get from the 400MP multi-shot option, though, my experience wasn’t very positive. Much like with the Sony Alpha 1, the 16 raw files consume vast amounts of space on your memory card and require piecing together in specialist software. But when you then examine the resultant DNG file, it doesn’t appear to contain usefully more detail than the camera’s standard 100MP files, while also being prone to showing imaging artefacts along high-contrast edges, or if anything moves within the scene. It’s a shame Fujifilm doesn’t offer a simpler 4-shot full-colour sampling option.

Fujifilm GFX100S: ISO and Noise

It should come as no surprise to see that the GFX100S extracts a ridiculous amount of detail from our test scene. There’s barely any visible difference in image quality from ISO 50 to ISO 400, and it’s only at ISO 800 that we start to see the slightest hint of blurring, which is most unlikely to be perceptible in print.

By ISO 3200 image degradation is more obvious, with most fine detail blurred away. But then again, you have so many pixels to play with that even ISO 12,800 should give quite acceptable A3 prints. However noise has a significant impact on the extended ISO settings, and I’d steer clear of anything above ISO 25,600. Click on any of the 100% crops below to see the full image (remember these are large files!).

Fujifilm GFX100S: Verdict

With each successive generation of GFX body, Fujifilm has made significant advances, but the GFX100S is by far its most tempting yet. By offering the same sensor as the GFX100 at barely half the price, the firm has further advanced the cause of medium format as a realistic upgrade over full frame. This is a camera that delivers sumptuous image quality in a remarkably easy-to-use package that takes up no more space in your bag than a high-end full-frame DSLR.

It’s also an extremely tempting upgrade for existing GFX owners. Compared to the two 50MP models, you gain double the resolution, in-body stabilisation and much better autofocus in a body that’s no less portable. For GFX100 users there’s the opportunity to shed considerable bulk and 400g weight with very little penalty in terms of capability. Indeed aside from a few specific benefits – the vertical grip, longer battery life without having to open up the camera, and the option of a tilting viewfinder – it’s very difficult to see why you’d now choose the older model.

So what’s not to like? To be honest, there’s very little to complain about at all. Where the GFX100 was occasionally guilty of style over substance, the GFX100S simplifies things down to what you really need. It’s the kind of camera that begs you pick it up and use it, then blows you away every time with its breathtaking results. In its own way it’s every bit as good as this year’s other super-camera, the Sony Alpha 1, and a better choice for those whose needs are skewed more towards resolution than speed. For professionals and committed amateurs looking to make really large prints, it’s a very compelling option indeed.

Fujifilm GFX100S: Full specifications