Fujifilm: Focus BKT is Blurry for last frame (INF focus) — Please Fix ASAP — You’ve Had FIVE YEARS 

2023-09-15 • SEND FEEDBACK |
Related: focus stacking, Fujifilm, Fujifilm GFX100S, Fujifilm medium format, Fujifilm mirrorless, medium format

re: Fujifilm GFX100S: Focus BKT Feature Shows 90% Failure Rate with Fujifilm GF 20-35mm f/4 and 35-70mm too

I don’t have any Fujifilm contacts, and I am unaware of any bug reporting facility I could use to get this problem fixed.

So I am going to vent here, hoping to get attention in the hope that someone out there can get the message through to Fujifilm.

With the new GFX100 II out, Fujifilm ought to pay attention to the serious pain it is causing by its firmware incompetence.

Fujifilm Focus BKT last frame does not reach INF

I estimate a 95% failure rate to deliver a sharply focused INF frame, meaning the Focus BKT feature rarely captures a frame that is sharply focused at INF (20-23mm range does better but also fails sometimes). Three lenses all show the same issue. At this point I’m certain it is has nothing to do with any particular lens.

This Focus BKT bug costs me a huge amount of time/tedium in the field, and sometimes makes me lose a shot entirely. Plus, in organizing my images, extra time and effort is required to locate the manually-taken INF frame and add it to the correct series folder. A major, MAJOR irritant and time-waster and shot-killer.

This broken behavior has gone on for five years, when I first reported premature termination of bracketing with longer focal lengths. Fujifilm, how can you let such a bad bug persist that long? How can you have such an incompetent team that the problem never gets fixed?

That the focus problem is obvious even at f/9 means a fundamental error in the code. Integer math rounded wrong (?)... OMG! A careless engineer together with an incompetent QA team that either failed to test, or tested incompetently. Either way, someone over there should be really embarrassed. Or maybe it is one of the denial things, so as not to lose face. Dunno.

Shooting a manually-focused INF frame makes it abundantly clear (by comparison) that the last frame which might have seemed sorta sharp in fact lacks all fine detail. Shame on you Fujifilm for letting this problem go on for five year, for not acknowledging it, and for not providing a process for reporting and resolving such issues.

I stand ready to assist and test any fix. But if nothing happens, then Fujifilm has my utter contempt, because to let this persist is despicable.

All I want is this bug fixed. Fujifilm if it is “too hard” to get it right, just do what Nikon does and shoot one or two more frames than your incompetent calculations suggest. A kludge, but it would fix it and you can release the firmware tomorrow. Note to engineer:

calculatedFrameCount += 2;

Below, a typical failure of Focus BKT. Frame 3 is the last frame of the Focus BKT series, with the camera set to take up to 29 frame and a step size of 4. INF_MF was a frame focused and taken after the series.

Frames 1/2/3 of Focus BKT (3 frames taken automatically), plus a manually-focused INF frame

f9 @ 1/20 sec electronic shutter focus stack 4 frames, ISO 100; 2023-08-30 18:53:41
Fujifilm GFX100S + GF20-35mmF4 R WR @ 27.3mm equiv (33.1mm)
ENV: Greenstone Lake, altitude 10200 ft / 3109 m, 68°F / 20°C
RAW: LACA corrected, vignetting corrected, WB 5500°K tint 20, push 0.66 stops, +100 Shadows, -100 Highlights, saturation -10, +30 Dehaze, +10 Clarity, AI Denoise 10, USM {8,50,0}, SmartSharpen{25,0.7,0}, diffraction mitigating sharpening, +10 Vibrance

[low-res image for bot]