A serious issue of Xt-3 firmware 4.0 update

JunChan wrote:

Hi all,

I am a Xt-3 user since 2 years. After the firmware update on my camera, there are some straight lines introduced occasionally in the footages. The straight lines will be shown when I tried to tweak the setting in Premiere and Resolve(15,16,17) on both mac and windows platform. To be more precisely described, when I tweak the curves of HUE vs Luma, I pull the red and yellow channel down, the vertical straight lines will appear. I attached a screenshot via my dropbox, you can see what I have done with the curve then.

Strangely, not all footages have this issue. I did a test with my camera and the XF18-55mm f2.8-4 kit lens, the lines will be introduced ONLY when the footage is shot with:

4K (UHD/DCI), ISO 1600 or above, Lens aperture f2.8, F-log

The lines will NOT be shown if the ISO is below 1600, Lens aperture in f3.2 or smaller, shot in Full HD in all kinds of camera/lens settings

A quick note: I discovered this issue firstly in Premiere when I was trying to color grade some footages. I thought it was the problem of the decoder in Premiere on windows, then I switch to Resolve on mac. The result is the same, but you will not see the lines with one single node. Because the curve in Resolve behaves much more gentle than Premiere, therefore it took multiple nodes with the same curve tweaking to introduce those lines in the footage. I have attached the screenshot of Resolve so you understand what I mean.

I have attached also an original footage shot on my camera, maybe some of you are interested to have a look and do some tweaks in premiere? The footage is set at:

4K UHD, ISO 1600/1250, Lens aperture f2.8/3.2, F-log, All-I, H.265

I exported the footage to "lines.mp4"(see attached). You can see the lines disappear because the ISO and lens aperture has been changed.

Here are the materials: https://www.dropbox.com/sh/b52aq7di6gxty64/AABILUMW8XkPut-y0FKgb-pEa?dl=0

I am not sure if this only happen on Xt-3, or even Xt-4 as well. I have already spoke to the CS of Fujifilm via email with some sample footages, but they insist that they don't see the issue at all. It will be great if any Xt-3 users can also do a quick test with their camera.

Stay healthy

I'm not seeing it.

I recorded with then settings you posted, same lens and adjustment in Resolve.

Take a look: https://www.dropbox.com/t/Q1oazaTkOijm8qcz