C300: C300 Mark ii ghosting edges

[NoahT]

Hi All,

I've been having some issues with getting a clean image out of the C300 Mark ii. High contrast edges appear to have a strong 'ghosting' effect that I'd really rather wasn't there. I've attached a sample image from a recent talking head segment. The first image is the C300 Mark ii with ghosting, and the second is the same shot from a 5D Mark iv B-cam without any ghosting present.

The sample was shot in 3840x2160 CinemaGamut C-Log3 25fps using Samyang VDSLR 35mm T/1.5. I also tested the Canon 24-70mm f/2.8 ii USM and the issue was still present. I suspected it could be a NR artefact, but setting NR to -1 did not help.


Has any one else encountered this? I'm new to the EOS C line and I'm at a loss on how to proceed with troubleshooting besides going through with a Canon service (costly and leaves me without an A-cam for several weeks).

I'd appreciate any insights!

 

[NorBro]

It's tough to tell what's going on here, but are you referring to the jagged edges? Aliasing?

The camera did have its share of artifact issues but usually in harsh light.

Maybe share a full resolution still or clip if you'd like.

 

[NoahT]

It's tough to tell what's going on here, but are you referring to the jagged edges? Aliasing?

The camera did have its share of artifact issues but usually in harsh light.

Maybe share a full resolution still or clip if you'd like.

The screenshots are of a white shirt collar with a shadow being cast across them. I don't have access (or permission!) to share full res frames at the moment.

I'm referring to the dark line that runs between the bright white and the shadow on the collar. The 5D seems to go from shadow to bright seamlessly, but the C300 adds an artefact between the two.

I'm not sure if 'ghosting' is the correct term. Perhaps aberration or fringing. The jagged edges aren't great either. I'm wondering if I've overestimated the quality I can get out of this camera.

Edit: I'm also fully willing to admit this could be user error

 

[NorBro]

Oh, I see now...yeah, I'm not sure but I think you'd be hard-pressed to pinpoint exactly what's going on.

If it's not user error in production (like maybe shooting in a proxy mode or something) or in post (importing or viewing the files incorrectly) then it's usually a combination of lighting, sensor resolution and processing out in the field.

The next troubleshooting step for many of us would be to set up a test and shoot something with different resolutions in the camera and the same lens at a few different apertures to see if something can be recreated.

One thing I've learned with cameras over the years is how the same box may produce drastically different images when set in different sensor modes. And definitely also how differently the stills and cinema cameras can behave when capturing video.

 

[cpreston]

It looks to me like excessive sharpening. Also, that doesn't look like Log Cinema Gamut footage, so I am thinking something might have happened in the translation to the viewing of the footage.

 

[NoahT]

You

It looks to me like excessive sharpening. Also, that doesn't look like Log Cinema Gamut footage, so I am thinking something might have happened in the translation to the viewing of the footage.

You might be right. I recall now increasing the sharpening setting as a test last month and not returning it to default... I'll test again next week. I found the C300 footage disappointingly soft when paired with the 5D iii and iv for multicam work, but I understand that to be a characteristic of cinema cameras when compared to DSLRs(?)

The footage has been graded and passed through a 709 transform lut, with no sharpening applied. The ungraded footage has the artefacts too.

The shirt collar is close to being blown out, so perhaps the in camera sharpening struggles with contrast in the upper exposure range. Definitely more testing required it seems.

Thanks for the suggestions.

 

[NorBro]

Sharpening in-camera is so deplored I couldn't even think of that as a consideration, lol.

Ah, sometimes a tiny bit is okay.

 

[cyvideo]

Are you sure the issue you are seeing is not related to the well documented, in many places, C300 horizontal bleed, venetian blind smear issue? It could be? Hunt around the web and you'll find discussions and video examples around. High contrast edges on wide dynamic ranges shots can cause the issue. Some posts some time back on this forum covered the problem.

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