Strange cubes in Fuji X-T3 FHD material

[zarazustra]

Hi all,

I just got myself a Fujifilm X-T3 and started playing with the amazing film features of this camera.

Unfortunately, I relatively quickly noticed some strange color defects in the FHD material this camera is producing for whatever reason (at least my model is). Did anybody else here notice similar behavior or is this some kind of user error?

Here is what I am seeing:

As you can see I have marked the affected area and also superimposed the frame grab to make the potential defect more visible. It is barely noticeable in the original material but once you know it is there... you know what I mean, I guess.

This only occurs at FHD and NOT IN any of the 4k modes shot in HLG or F-log.

The above is shot with 1/50s at F8 with ISO 1000.

You can also notice it in the finder if you start looking for it. Furthermore, I noticed that depending on the aperture setting these blocks seem to start moving to other parts of the picture...

Is this a known problem or something new?

[thephoenix]

what were your settings ?

[Andrew Reid]

Try H.264 instead of H.265... Oh and take the lens cap off

[zarazustra]

Haha very funny... That's a good start on this forum. I feel welcomed.

In case you were wondering why the image looks so disgusting it is because I lifted the shadows of the grabbed image quite a bit in post to make the defect more visible. But trust me, it is there, also on a properly exposed image. It is just much much more difficult to notice.

I did not notice it at first either. It was rather a coincidence when my gimbal accidentally tilted upwards and let me record the blank white ceiling for a bit! That was the moment where I thought: S***!

Anyways, it definitely should not look like this.

I have yet to make more tests. How about the high-speed mode e.g.... I hope it doesn't show up there as well.

Settings: anything particular you might want me to look up? There seem to be a myriad of settings...

The basics are already mentioned above: All manual, shot at 1/50s, f8, ISO 1000, 25p, FHD.

Lens: Fuji 18-55mm kit lens @18mm.

As profile I have set it to Etherna, but does that actually matter if f-log or HLG are engaged?

In terms of modes, here is what I tried:

F-log, Long GOP, All intra, various bitrates, HLG... With a B+W Vario ND and without... Doesn't matter...

As soon as I switch to FHD rather than 4k the blobs start to appear. Randomly. You can even notice them in the viewfinder and the back screen.

The only link I seem to have noticed is with the dialed in aperture. Depending on the settings the squared blobs start to move across the image. But they keep their straight edges, so it feels like some digital artefact rather than anything introduced from the optics.

Once I switch back to anything non-FHD all is good. No color shifts and no blobs.

Scene: Shot at rather dim light. Straight against the white ceiling. Then as described various aperture settings to stop the light. For me the effect is immediately noticeable once you start looking for it even when shot wide open. It manifests itself by introducing rectangular sections of the image which show some sort of micro colour shift in those areas. Kind of a bluish one. When you grab a single still from the recording and superimpose it, like above (e.g. via Levels in Photoshop), you should get something similar to the image I posted... or not, if you are more lucky than me

Could someone with the same setup maybe do a quick test as well and report back their findings?

[Attila Bakos]

You mentioned that it happens in various bitrates, but does it happen in both H.264 and H.265?

[jpleong]

Also, what's your NLE and OS?

I use Premiere on a Mac and had to turn off hardware acceleration as it was introducing artifacts in my 4K F-LOG h.265 footage. I haven't looked back at my HD footage from the X-T3 but you never know?

[zarazustra]

Here are some examples...Straight from the camera.

All FHD, F-log... notice the terrible blocks in the middle of the image.

https://we.tl/t-clu687kQEJ

https://we.tl/t-v4aJ7EN7dp

And here is the same settings in 4k... clean as it should.

https://we.tl/t-cZ9bwoYaiM

Notice that the blobs are also showing in the viewfinder / back display in the 4k modes. But in this case they disappear as soon as you start recording.

I tried HLG mode as well... same thing

Can someone comment on their experience? I have to determine what to do with this camera...

[Attila Bakos]

Just tested it with similar settings and conditions, my unit doesn't have this issue.

[Andrew Reid]

Said it before, will say it again. Try H.264.

[Attila Bakos]

6 minutes ago, Andrew Reid said:

Said it before, will say it again. Try H.264.

One of the files he uploaded is actually H.264.

[jpleong]

Is it my imagination or are the "FHD" clips reporting back as 2048x1080?

 

EDIT: duh. didn't realize the X-T3 records 2048x1080, too.

[Andrew Reid]

Try inter-frame NR off.

It might be related to that.

I'm wondering if this is all a bit pixel peeping gone mad to be honest. All cameras look shit if you shoot at F8 with lens cap on don't they, and try to pull up garbage from the compressed shadows. Even raw looks a bit rubbish in that circumstance.