FS5 Weird Blue Fringing in HD SLOG 3 at DVinfo.net

Aaron Tan CM · December 18th, 2015, 10:27 PM

I just got my camera yesterday and been playing around with it at home. I'm getting a weird blue fringing along edges that separate light and dark areas. At first I thought it was peaking but it wasn't turned on in the camera. This blue fringing is recorded in the footage and it's pretty nasty.

Seems to happen only when shooting in HD (I'm currently set at XAVC HD 1080 25p 50mbps). I haven't had time to do a proper test yet to see where and when exactly this happens but going through the picture profiles it seems to happen mostly in SLOG 3. It's there but less obvious in SLOG 2 and doesn't appear in normal Cine Gammas. It also doesn't appear very obviously in UHD in any picture profile setting (but it's there just slightly when using focus mag)

I've attached screenshots in the link below. One is HD and one UHD. You'll be able to tell which by the blue fringing. Compare the clothes rack in the middle of the room and the window frame. Anyone come across this on their cameras?

https://goo.gl/photos/tKHY8hjQCb9AuzE8A

Christopher Young · December 19th, 2015, 05:37 AM

It could be CA (chroma aberration). What lens were you using? If it's anything like the FS700 it can produce CA with various lenses, some worse than others. The cleanest images I have seen for lack of CA and corner fall off are the Sony e-mount lenses that communicate with the firmware in the camera. If it is lens CA you should be able to confirm it by shooting the same scene you have shown us but at various apertures to see if you can increase or decrease the effect.

Or it could be a well know aspect of Bayer sensors that has appeared on many a Bayer sensor at certain times. Usually seen on extreme contrast transitions. It's called:

False color artifact.

A common and unfortunate artifact of Color Filter Array (CFA) demosaicing is what is known and seen as false coloring. Typically this artifact manifests itself along edges, where abrupt or unnatural shifts in color occur as a result of misinterpolating across, rather than along, an edge. For preventing and removing this false coloring various methods exist. Smooth hue transition interpolation is used during the demosaicing to prevent false colors from manifesting themselves in the final image. However, there are other algorithms that can remove false colors after demosaicing. These have the benefit of removing false coloring artifacts from the image while using a more robust demosaicing algorithm for interpolating the red and blue color planes.

Take a look at this page for more:

https://en.wikipedia.org/wiki/Bayer_filter

and this one:

https://en.wikipedia.org/wiki/Chromatic_aberration

Chris Young
CYV Productions
Sydney

December 18th, 2015, 10:27 PM	#1
Aaron Tan CM Tourist Join Date: Nov 2009 Location: Singapore Posts: 1	FS5 Weird Blue Fringing in HD SLOG 3 I just got my camera yesterday and been playing around with it at home. I'm getting a weird blue fringing along edges that separate light and dark areas. At first I thought it was peaking but it wasn't turned on in the camera. This blue fringing is recorded in the footage and it's pretty nasty. Seems to happen only when shooting in HD (I'm currently set at XAVC HD 1080 25p 50mbps). I haven't had time to do a proper test yet to see where and when exactly this happens but going through the picture profiles it seems to happen mostly in SLOG 3. It's there but less obvious in SLOG 2 and doesn't appear in normal Cine Gammas. It also doesn't appear very obviously in UHD in any picture profile setting (but it's there just slightly when using focus mag) I've attached screenshots in the link below. One is HD and one UHD. You'll be able to tell which by the blue fringing. Compare the clothes rack in the middle of the room and the window frame. Anyone come across this on their cameras? https://goo.gl/photos/tKHY8hjQCb9AuzE8A

December 19th, 2015, 05:37 AM	#2
Christopher Young Trustee Join Date: Apr 2008 Location: Sydney Australia Posts: 1,571	Re: FS5 Weird Blue Fringing in HD SLOG 3 It could be CA (chroma aberration). What lens were you using? If it's anything like the FS700 it can produce CA with various lenses, some worse than others. The cleanest images I have seen for lack of CA and corner fall off are the Sony e-mount lenses that communicate with the firmware in the camera. If it is lens CA you should be able to confirm it by shooting the same scene you have shown us but at various apertures to see if you can increase or decrease the effect. Or it could be a well know aspect of Bayer sensors that has appeared on many a Bayer sensor at certain times. Usually seen on extreme contrast transitions. It's called: False color artifact. A common and unfortunate artifact of Color Filter Array (CFA) demosaicing is what is known and seen as false coloring. Typically this artifact manifests itself along edges, where abrupt or unnatural shifts in color occur as a result of misinterpolating across, rather than along, an edge. For preventing and removing this false coloring various methods exist. Smooth hue transition interpolation is used during the demosaicing to prevent false colors from manifesting themselves in the final image. However, there are other algorithms that can remove false colors after demosaicing. These have the benefit of removing false coloring artifacts from the image while using a more robust demosaicing algorithm for interpolating the red and blue color planes. Take a look at this page for more: https://en.wikipedia.org/wiki/Bayer_filter and this one: https://en.wikipedia.org/wiki/Chromatic_aberration Chris Young CYV Productions Sydney