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.
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.
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.
After spending a few weeks with the Sigma 50mm ƒ/1.4 Art, I've come to realize maybe Sigma lenses aren't the solution for me. At least the 50mm has a very short focus throw, making manual focus a tedious process, even with focus aids like focus peaking and focus zoom. Autofocus is just too unreliable and slow to depend on for all occasions, making manual focus capability a priority.
One thing I quickly discovered is the intrusion of the lens hood when adapting 35mm lenses onto the medium format GFX. Since the 50mm Sigma casts an image circle closer to 40mm, it's going to pick up more of what's on the periphery of the field of view; in this case it's the lens hood.... Continue Reading →
If you'd like to contribute your findings, please include lens specifics (brand, focal length, maximum aperture, lens version, firmware version, and if it's weather sealed or stabilized), adapter used, and camera used. Full sensor sample shots without the lens hood (JPEG, 2000x1500 pixel minimum) needs to be of a white or gray background at the widest aperture at both minimum and infinity focus, repeating this at ƒ/8 and at minimum aperture, be it ƒ/22 or ƒ/32.
This is the first in a series of posts on individual lenses adapted to the Fujifilm GFX 50S with the TechArt Pro EF-GFX adapter. Fujifilm GFX 50S, firmware v3.30 (latest) TechArt Pro EF-GFX, firmware v1.01 (latest) Sigma 50mm ƒ/1.4 Art, firmware v2.02 (latest) Summary: Full compatibility: Autofocus, EXIF OK. This lens shows a correctable vignette throughout the aperture range but is heavily affected by focus breathing. As the aperture shrinks, focus toward infinity causes the vignette to become harder and more pronounced. Despite this, it is easily cropped and corrected while maintaining 45mp or more.
As I have alluded to in a burst of recent posts, I am planning to generate a small database of lenses for use on the Fujifilm GFX series. Here's my chance for an introduction to give my rationale and to lay the foundation of this endeavor. I'd like to break this down into three "Y's." Let's begin with a personal "why": I'm choosing to use Sigma lenses to obtain focal lengths and apertures not currently offered in the GF lens lineup. Fujifilm's lineup is sparse at best, and apertures wider than ƒ/2 aren't represented. It's not that I'm a bokeh whore; it's that I need more light gathering for astrophotography and Fujifilm's widest lens, a 23mm, has a maximum aperture of ƒ/4 and that's just not going to work without a star tracker due to the sensor's 51MP resolution. I'm hoping to print a few of these so what counts for "sharp" on the web doesn't work at 20" print sizes. Other benefits: 35mm lenses are much cheaper, especially used prices, and these lenses mostly have direct focusing units unlike the "fly by wire" systems used on Fujifilm lenses. The GFX system just isn't mature enough to have grown both a complete lens lineup or a diverse used lens market.