Sony FS5 user reports artifact issues triggered by changing exposure, ND. Visible on HDMI output

A growing number of Sony FS5 users are reporting image quality issues with the camera. Leading on from issues highlighted on Newsshooter by Paul Antico, other users have also found strange artifacts in various different modes and sensitivities. This has sparked debate on several of the popular online forums with some users seemingly happy with the camera output, while others are less than impressed.

I have to admit that when I reviewed the camera in quite glowing terms a few weeks ago I hadn’t spotted anything in the images to upset me. In hindsight I should have tested more thoroughly – especially in 4K. I had to return the camera after a few days and haven’t had one to verify any of the claims. Hopefully I’ll be able to get my hands on one again in the coming weeks.

Max Wagenblass's Sony FS5
Max Wagenblass’s Sony FS5

Max Wagenblass of boutique production company Glass Ink Media has been in touch to more highlight strange tearing artifacts at high ISO. He claims these are showing up not only on in-camera recordings, but are apparently visible on the HDMI output and on the built-in display (when magnified). Even more worryingly he reports that the artifacts are triggered when the exposure is changed while filming.

Ramping the variable ND caused lines to wobble and block/spike the same way as when panning vertically.

This is what Max had to say:

OK, so I finally got around to doing a longer test. In this video, I go through all the FS5 gammas. For post workflow, I put the UHD .mxf file into a 1080 timeline and did not resize, so what you are seeing is a pixel-for-pixel representation (no downscaling or interpolation). Keep an eye on the moulding of the window sill. Download the 1080 file if you’re having trouble seeing it in the embedded player.

I used factory default picture profiles so that anyone who wants to know the specific picture profile setting I used already has them available on their camera. But please don’t misinterpret this as meaning that it happens only in factory default settings. Every picture profile parameter tweaked has no effect on reducing the artifacts.

Other notes:
UHD 24P (though it’s the same in 30P)
Artifacts visible the same on uncompressed HDMI, and on camera monitor (this is NOT an XAVC, or post workflow issue).
Clear image zoom off

My building is very old, so apologies for the gross looking window sill and wall 🙂

My conclusion: The artifacts show up in all gammas, though in S-Log they start to appear at higher ISO’s than the other profiles. One new thing I discovered doing this test was the artifacts can be triggered by changing the exposure while filming. Ramping the variable ND caused lines to wobble and block/spike the same way as when panning vertically.

If Max’s findings are true this would add another level of complexity to the problems already identified as this is not resulting from XAVC-L encoding or a low bitrate. It may therefore result from some other image processing going on inside the camera.

We don’t know at this stage whether this is a fault with Max’s and other users cameras, or is an issue with all FS5 cameras. It may be that the issue is related to camera setup, but if it is then Sony need to tell us what the correct settings are as it seems Max and others have exhausted all possible options. I would hope that Sony investigate the matter and provide a fix in the not too distant future.

So far these findings, if true, don’t change my earlier conclusions about the FS5’s overall suitability for documentary and broadcast shooting, but if you spend a lot of time recording in 4K in low light then maybe hold off getting one until Sony addresses the issues directly.

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