UPDATE: this note from Ahmed looks to be in error, see Chris D’s comment that follows.
Regarding the Fujifilm GFX 50s firmare update, Ahmed G writes:
Japanese guys from Fuji contacted me to say with the new firmware GFX will focus at the aperture you have selected.
It was always focusing wide open then stop down which made the focus shift.
But now it will focus at the selected aperture.At their firmware update info they did not mention it but it works :) I think they do not want it to be known as an update. Please try it your self and see.
DIGLLOYD: if true, this is terrible news. Focus shift with the Fujifilm lenses is minor and not a serious issue. So stopping down is a solution in search of a problem with other worse ramifications.
It means that if you want to shoot at say f/8 or f/11 or, you’ll have to twiddle the aperture open to focus, then close it down again to shoot. This is a problem even at f/4 or f/5.6. For manual focus or autofocus it’s a big problem. I spend all day wasting my time over and over doing this with Sony. It is a major hassle doing focus stacking with Sony for this reason; it simply cannot focus where desired with the lens stopped down.
No human eye or camera autofocus can precisely focus where desired when stopped down beyond about f/4. I know this from repeated problems with Sony and other cameras, manual focus or autofocus. It is easily proved: focus on some critical target at, say, f/8, then open up to full aperture and zoom in— most of the time it will be blurry there, showing that the camera cannot focus precisely when there is too much depth of field. Of course it cannot—that’s the whole point of depth of field—a deeper zone of critically sharp focus. The camera AF (or human eye) cannot tell focus at 30 feet from focus at 50 feet if f/8 or f/11 is making it equally sharp.
Chris D writes:
Just tested this claim with the old firmware, and then the new firmware after updating the camera. The new firmware does not alter the AF behavior with regard to the aperture - it’s exactly the same The lens does not focus at the selected aperture in AF.
Peter F writes:
I promise that this will be my last comment on the 1.11 firmware update I wrote to you about a few days ago, and is in response to Ahmed’s post on your blog today.
I updated, and today drove around 200 miles around South East England and made many photographs with the GFX and 63mm lens in a huge range of situations, interiors, outside close ups, middle distance and far distance scenes, at apertures from f2.8 thru to f22 and have been astounded by the extraordinarily consistent spot on focusing in all cases, from 15” away indoors, to infinity outdoors…and all distances in between, only using autofocus.
If the camera is now focusing at the taking aperture it’s doing an incredible job. The camera I now have working is the camera I dreamt of years ago...quite amazing, and I am an exhibiting professional who often makes prints 40” x 60” and larger. I’m stunned with the turnaround.
DIGLLOYD: sounds encouraging. However, claims that focus is spot on at f/8 (or f/22!) are misleading at best, because of the depth of field involved. One has to look at the zone of focus and where sits relative to the chosen point of focus. It is easy to have that zone too far or too close, and yet the “spot on” comment might well apply always or nearly so! So it sounds encouraging but I am not encouraged by this summary statement. One has to do the right test, which is to nail the focus at full aperture (focus that way), then stop down and shoot. Then compare that ideal result to 5 or 10 AF results focused at the taking aperture.
Eric B writes:
I don’t know about the GFX, because I cannot afford one either, but with my XT-2 if I use autofocus, shutter AF, and partially press the shutter release, it stops down to the shooting aperture.
If I set the camera to manual focus, turn off shutter AF in the menu, and use the AF-L button to focus (back button focus) it does not.
It stops down a tiny bit but certainly not to a shooting aperture of f/5.6 or smaller. when I use back button focus. If the camera is set to autofocus, either AFS or AFS, to stops down even with the AF-L button. It’s more complicated to explain than it is to do. In summary, with the XT-2, just set the camera to manual focus, turn off shutter AF, and use the AF-L button to focus. I’d love to know if it’s the same behavior as the GFX. I started using back button focus years ago with my D800E and except for fast moving situations, continue to use it. Your comments would be welcome.
DIGLLOYD: I've seen variable behavior and I’m dubious it is so simple—what I means is erratic behavior that may depend on lighting brightness and other factors, making it unpredictable as a reliable and predictable tool. But I don’t have an XT-2 to check. I also generally use only the rear AF-ON button. See my Sony setup guidelines for how I like to setup up Sony cameras; similar ideas apply to Fujifilm.