Where the Sigma 85/1.4 is a home run, the 35/1.4 is a bit of a mixed bag. For most people, it should be fine. For some, like me, it's borderline acceptable. For those few, it will be unacceptable. In 35mm crop mode, it works just fine, but for any other mode, it will require a bit of cropping and correction. At wide open, there is a bit more smearing in the extreme corners that sharpen up by ƒ/4 to 5.6.
The Sigma 85mm seems to cover all of the imaging sensor with no hard vignetting. Fitment of a Wine Country Cameras 100mm filter holder does cause some very light vignetting at the extremes but is easily correctable. Image quality at the extreme corners and edges is a bit compromised at wide open but shapes up when stopped down to ƒ/4.
When the X-H1 was introduced, it was described as a sibling lineup; specifically an approximately 60/40, video-weighted hybrid that also shot great stills. It had a larger body and grip, not just to facilitate the IBIS system, but to give it better balance with larger cinema lenses for owners seeking a capable video camera. The X-T series was defined to be exactly the opposite ratio; a stills-centric camera that also shot great video. However, like the odd inclusion of a factory adjustable leaf spring shutter switch on the X-H1, a feature that's more coveted by stills shooters, the X-T4 has also incorporated a couple of weirdly out of place features that betrays Fujifilm's original description of the X-T series being stills-focused.
I suffer from PTSD related depression that often fears its head during points of boredom. As such, I try to keep myself as busy as possible. It doesn't have to be physical activity, but anything that keeps my mind busy. That means winter can be when I'm at my darkest due to the weather, as my mobility is shunted due to physical disability and limited opportunity to do the things I love most. It's rained just about every weekend since December, and the 1 or 2 dry weekends were tarnished with a week's worth of rain or snow. Unless there's a specific need, I'd prefer to not camp in the rain or snow. After seeing Jay's macro product shots, I decided to do some floral macros, since I have an arrangement of gerber daisies that's survived since Valentine's Day. I didn't break out any lighting, shooting at ISO 4000-6400 and 1/100s shutter speed with a Sigma 50mm ƒ/1.4 DG Art on the GFX 50S. Figured I'd try and adapt my muscle memory for a focusing ring that rotates opposite of all other brands. Anyways, I really need to get outdoors. Hopefully the weather this weekend works out.
Despite white wall tests of the Canon EF 28mm and 135mm lenses showing acceptable levels of vignetting, my first real world use of them ended in failure.
Eye-AF works pretty well with this combination. Focus is slow, but it's able to find and lock onto an eye. Because of my experience with the X-T3, sometimes my expectations can be a bit skewed; face and eye detect on the 2018 X-T3 is quite good, especially on distant (small) faces as Fujifilm has improved by leaps and bounds in this area. How quickly I forget the GFX 50S is over a year and a half older, with an imaging processor based on the X-Processor 3 design in the X-T2 and not the current X-Processor 4. Combined with other hardware limitations, plus the fact that the latest firmware update was over a year ago, eye AF on the GFX 50S (or 50R, for that matter) cannot be expected to perform anywhere near that of my X-T3.
Since buying this head, I've quickly learned to love it, especially after buying the necessary hardware that allows me to invert it as needed. The smooth design, reliability and light weight has helped it find a permanent home atop my Gitzo GT1542 Mountaineer tripod, supplanting the GH1382QD ball head that came with it.
There are some drawbacks though. Uncannily enough, they’re the same as with the Canon EF 28mm ƒ/1.8 USM: slight vignette with a hard vignette at infinity focus. At ƒ/8, it isn’t very prevalent as you’ll see in the samples, easily corrected with a 5:4 crop that retains 48MP. However, as the aperture gets smaller, the vignette hardens, as you can see at ƒ/32, but still works at a 5:4 crop ratio. The lens works fine with a 3:2 crop at full sensor width and in 35mm crop mode, so you can choose what works best for you. Weirdly, the lens changes focus as you move in and out of playback mode on the GFX...
Widening out to an approximate 22mm in 35mm format terms, the Canon EF 28mm ƒ/1.8 USM does show some hard vignetting that is never fully resolved. It’s very, very slight and occurs at ƒ/4 and smaller at infinity focus. Vignetting is prevalent fully open, mostly disappearing by ƒ/4 at close focus distances. If the vignetting is a problem for you, the EF 28mm ƒ/2.8 IS might be a better bet but isn’t on Canon’s list of preferred lenses for the 5DSR, so it may or may not resolve well on a 50MP sensor.