FS7: Is color shift of highlights existing (and maybe avoidable)?

A

A7s_user

Active member
Sorry for disturbing, but I really need help, please.

I am not filming persons/real live but large scale fireworks displays (at eg. international competitions) only. This might be a ridiculous task for some, but I want and have to deliver high quality footage with the most realistic and natural colors and lowlight golds to the companies contracting me.
Till know I've used an EX1R, which does record perfect fireworks colors with its 3CMOS sensor. I want to change to 4K for some reasons. I've tried the A7S in the last months and trapped into its extreme color shifting of highlights (lights, flares, fireworks stars, LEDs...), which seem to effect all modern 1CMOS sensors in Sony cams. I know it for the CX700/900, the AX100/PX70 and for my A7S. The gamma mode or color matrix do not matter, especially some reds are always fully shifted to bright intense orange, greens and blues are less but noticable shifted towards cyan. The results of the A7S (expecially its incredible red shifting to orange) seem to be uncorrectable in post (at least for me as color grading noob). Changing the color depth for CMYRGB in the A7S settings slighty reduces the shifting effect, but its still destroying colors.

That's the story. Since there is no sign of a rumour of a Sony 3CMOS 4K sensor I have to find another solution.
I really do fear the same behaviour with the FS7. I would love to buy that camera, but why it should be different?
So, here are my questions:


  • does the FS7 suffer the same extreme color shifting of bright intense highlights?
  • is it somehow possible with some matrix settings in the cam, to avoid that possible shifting at least maybe for 80-90%?

Any help/hope is appreciated. Thanks in advance!
 
I've never tested my FS7 for bright highlights and colour shifts. I've mostly shot small commercial work that was lit and have never shot with standard gammas.
 
Slog3 has a much smoother colour roll than 'baked' looks on the previous sony cameras.

The sony sensor still seems to ge 'exited' by LEDs
 
I've not noticed any highlight shifting, though I'd have thought a camera with no rolling shutter would be a solution than either the FS7 or A7s.
 
I did found some videos filmed with FS7 and as it looks like filmed with slog3, eg:
https://www.youtube.com/watch?v=ElxKbMAzf5M
https://www.youtube.com/watch?v=AgR04yDSvhI

I don't like the slog-tint for fireworks, I would not like to use it. Its simply not natural for fireworks. I did not succeed with slog2 on A7S, even after reading and understanding the LUTs/explanations of Alister Chapman and trying in color grading. There remains a pale-greenish slog-tint in the video. Nice for cinematic look of skins, but disturbing when I expect realistic clear fireworks colors. But this is only my taste and probably I have to try more.

But have a look starting from 21:20 in the second video. Although that orange could be used intentionally, orange color is very seldom used at fireworks. I looks like the full color shift of slighty yellowish Calcium-salt based red-colors, as it happens with my A7S. That would be just the deal breaker for the camera. I need to compare that show filmed by a non-sony-cam....

@Liam
Rolling shutter is not that problematic. Not nice, but accaptable.
 
That was my BIG issue with the FS700 is the major red color shift to orange when using S-Log2. I tested my friends A7s and it had the same red to orange issue. I hated it so much. It's actually fairly easy to fix in post. In your color program, I use After Effects mainly, just go into the Hue filter and select the Red channel, then shift the wheel a little bit and it brings back the orange to red. Not ideal, as it can shift skin tones a tiny bit as well.

I am very happy to say that reds are much better on the FS7. They actually look red as opposed to orange. Reason enough to buy the FS7 right there.
 
Thank you all!
Ooohh, all signs point to "FS7 but use with s-log3". Noah recommends the same here too.

Really, I am unsure if this pale-greenish tint is fully removable in color grading. You pros may confirm, but I saw so much typical slog-tint videos here/on Vimeo that I am very unsettled. The two youtube videos above are very bad for my taste.

@gene
I will try the hue filter with some footage of my A7S. Problem was always, that orange black powder sparks gets reddish too...
 
Yeah, I hated the red to orange thing so much in the FS700 Slog2 that I was willing to pay $8K on the FS7 just for that fix alone.
 
@gene
But is it fixed in the FS7 with a cinegamma or 709 too, or just with slog3?
 
Last edited:
I only used CineEI + SColorGamut3Cine + Slog3 and sometimes I will bake in the LC709a LUT, and yes it's fixed in those modes.

Can't comment on the other modes because I never use them except for testing purposes when I first got the camera and I wasn't paying too much attention. Nothing jumped out at me though in Custom or Hypergammas.
 
morgan_moore said:
Certainly you get shifts in other modes.

I dont think properly lutted Slog3 is wooden though.

S
Click to expand...


Hi,

I know that I should not film s-log the night because of the noise, but as only slog3 would know how to keep red... red, I have just tried, by my balcony.
I am not colorist, it is thus very fast made.
But on the first shoot - "french food", the neon must be red for example...

https://vimeo.com/192012423
pw : jo

Can be that fs5 done well less than fs7?

Have you ever tried some shots like these ?

I am asking because I am working on a project, where the fs5 is in background of the stage, and where the 3 other cam (sony PMW300) seem to work better.

PMW300 :
PMW300.jpg

fs5 :
fs5.jpg

We cannot figure how to fix this !

Any idea ?

Thanks !


(nb : I read the forum for a very long time but it is my first message! :) )
 
Last edited:
You don't have to be a colourist, very simple secondary correction, either keying or vector or hue curve, is all that is required to match the colours.

But you don't say what software you're using so it is impossible to give you any specifics.

You don't say what LUT you're using to get from SLog3 to REC709. Maybe consider buying LUTCalc and building a LUT that will match your PMW300 as a one stop shop.
 
Nirv said:
You don't have to be a colourist, very simple secondary correction, either keying or vector or hue curve, is all that is required to match the colours.

But you don't say what software you're using so it is impossible to give you any specifics.

You don't say what LUT you're using to get from SLog3 to REC709. Maybe consider buying LUTCalc and building a LUT that will match your PMW300 as a one stop shop.
Click to expand...



Thank you. I used sony lut. Ok for the simple correction, I think I can do this. But there will be a colorist at the end of the 8 shows we are shooting, so I don't worry about this, if it is simple.

I just wondered how to fix it in camera !


And I was surprised by the treatments of red neons lights... It seems not to be red as said, even in slog 3 !

But thanks again for your answer, I'll check LUTCalc.
 
You must log in or register to reply here.
Back
Top