Fujifilm GFX100: Horizontal White Stripes a Problem for Numerous Images from my last trip
Related: black and white, Contrast and Phase Detect Autofocus, digital artifacts, filters, focusing, Fujifilm, Fujifilm GFX100S, Fujifilm medium format, Fujifilm mirrorless, medium format, noise, pattern noise, PDAF banding and striping noise, polarizer, reader comment, striping pattern noise, Walter B
The horizontal white stripes on the Fujifilm GFX100S that I reported on might be related to PDAF banding, but it’s not clear that it is the cause. PDAF banding as I understand it usually causes dark stripes, not light ones (so why is "banding" used instead of "striping" anyway?).
I’ve added 3 more examples with Adobe Camera Raw settings showing the issue, which I can reproduce at will on most images.
To be clear, my concern about the stripes has little to do with color photography, and (almost) everything to do with being able to make a monochrome rendition for landscape images.
Fujifilm GFX100S
Walter B writes:
Appreciate all that you have reported and did not buy into the camera based on the fact that I work in black-and-white exclusively.
But since both J and C have the Fujifilm GFX100S and are testing it extensively, I thought these two would be able to help identify “issues” with the camera and lenses. They have mentioned some to me, but nothing related to banding. However, I have asked both to see if they can show me their practical examples of PDAF banding. Subsequently, J tortured one image to find a small banding area in a blown out overexposed area essentially shooting into the sun, he said he found some. Looking at the files, I could hardly see any.
C has sent me several RAF files which I tried to subject to the settings you used in your blog post Fujifilm GFX100S: Horizontal White Stripes - the Futility of Using GFX100S for Monochrome Landscape Images. (I used C’s image @ 100% to match your settings in LR, Color & B&W) Please review the first two images attached. Unlike your examples, C did not use a polarizer.
Your blog post "Fujifilm GFX100S: Unacceptable Image Quality for Monochrome Images - Horizontal White Stripes”) indicated you used a polarizing filter.
Looking at another blog post example (“PDAF Pimples”) I could not tell if a polarizer was used.
The last two images (again a section of C’s RAF file @ 100% without polarizer) used the settings illustrated by Jeff K in your blog post "How will the Fujifilm GFX100S Fare as to PDAF Banding.” Again I could not see any banding.
But try as I have using C’s RAF files and various LR and PS settings, I could not find any hint of PDAF banding.
I currently use the Pentax 645Z and hope to one day shoot identical images, one with the 645Z and one with the 100S should J or C and I meet up. But until then I am trying to find a reason not to buy into the GFX 100S.
You have made strong arguments but I cannot reproduce the banding and wonder why? What do I need to do to verify the issue? Could it be that the polarizer accentuated the PDAF banding? Do we need to send C to a remote location at 10,000 feet to eliminate atmospheric clutter? I am sure he won’t mind.
What am I doing wrong not finding banding?
P.S. As you suggested, I bought and am using the NEC PA302W and love it! Thanks for that one.
DIGLLOYD: I’m sure it is not related to use of a polarizer, since I’ve proven the issue exists without one. It is also not an 14-bit/16-bit issue. See my conclusions in Don’t even Think about Using the Fujifilm GFX100S for Monochrome Landscape Images — Horizontal White Stripes Make Images Unusable.
Responding to Walter B, I selected 3 images from my last trip semi-randomly, and all showed the horizontal white stripes. Moreover, it doesn’t require use of the filter; the adjustments alone can show the issue.
I sent them along with processing settings to Walter B:
These are awful!!!!! Not sure why I cannot do the same but it does require caution on my part.
Actually waiting for the Sony A7R V hoping it has a new sensor and focus shift, my Nikon Z7 does as you know and it is fun to use.
I consider it proven that the Fujifilm GFX100S is a total fail for monochrome landscape imagery. Moreover, "C" has the camera I sold to him, so his findings merely indicate that the conditions did not produce the striping. You cannot prove absence of a problem by not finding it in some cases.
Why or how the horizontal white stripes appear or do not appear—I don’t know. I suspect that it is more of an issue at high altitude perhaps due to blue light, but that is only a hypothesis at this point.
The horizontal white stripes appear 18 pixels apart over the entire frame (14-bit and 16-bit). What on the sensor corresponds to that spacing? PDAP pixels perhaps?
