A7S colored highlight peaking?

I have this problem all the time concerning LED lights with the FS700. Makes me nervous about the a7s now. I can try to sneak a test tomorrow, but I probably won't be able to post results until the following day. I will see what I can find to duplicate these results. Here's hoping it's a camera defect in your a7s (even though that would be sad still).

**Update**

Found an LED star that switched from red, green, and blue. Blue LEDs are not your friend for this camera, like the other sony cams. Blows out as bad as OP's pics. The other colors were better, but on skin tones specifically, blue has it in for this camera. Bring that second, different camera on the next shoot, I know I will.
 
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Yeah this was unmodified PP7, no color grading, those are screen grabs straight from the file, and it did look like this in camera on the screen, I was thinking "wtf?" when i was filming it because my C100, while darker, was not producing these effects.

The first pictures I posted were at 24fps, and those recent ones were at 120 as I was trying to get some slow motion dancing, but either frame rate the bad coloring still appears.
 
I did some testing using my LED computer monitor as a light source, and turning it pure blue.
Here's something that shows promise - in whatever picture profile you're using, go to Color Depth and turn B up to +7.
 
Could it be something to do with UV pollution? I think blue LEDs are supposed to emit a lot of UV (they're actually considered to be hazardous to eye-health). I wonder if a UV cut filter might help?
 
Ralph B, I noticed that as well with color depth. Just not sure if darkening that value would affect skies in a negative way. Need to test that.
 
I've seen blue lights peak out in dark areas where the ISO gets pushed heavily on my A7s too. My guess is it's how the camera is designed.
 
There are very nice LED lights, they are just not the ones people use...

I bought a few 50W Cree LEDs rated at 3000K and CRI90+, and designed a fresnel for them with my 3D printer and some optical glass. I think they look really nice, and can nearly match the power of my 650W tungsten fresnel at a fraction of the power and, above all, heat.

I do plan to sell them when I've finished the design.
 
Samuel H said:
There are very nice LED lights, they are just not the ones people use....
Click to expand...
Exactly. And live venues (except for maybe a few super high end ones) are not gonna get them in any foreseeable future. So for filming live performances you're gonna be faced with ugly LED lighting :(
 
I have a similar effect only when I use an old Pentax 1,4/85 mm prime. When there is a little backlight the highlights turns in a kind of blue. I could not reproduce this with the Sony FE 24-70mm.
Benn
 
I can reproduce the issue on a color ramp chart and it appears to be a significant discontinuity that only exists in the blue channel a few stops before clipping, right before the point where the highlight primary color shifting issue takes place. It is different from the highlight primary color shifting issue* which I have seen in nearly all Sony cameras. The issue seems to occur in all picture profiles with all gamma curves and all color modes even including Black & White. It also occurs in PP OFF if creative style is set to Standard, Vivid, Neutral, Portrait, Landscape, Sunset, and Night Scene. The issue does NOT seem to occur in CLEAR, DEEP, BLACK & WHITE, SEPIA, and AUTUMN LEAVES. Alternatively, the issue seems most greatly affected by white balance, where in my tests the issue was greatest around 2500K and quickly diminished as WB was adjusted upwards and the issue seemed nearly imperceptible by around 4700K.

Currently I'd say if you are in situation with strong blue lights and are experiencing the issue first try increasing your whitebalance or switch to PP OFF and a creative style of CLEAR, DEEP, BLACK & WHITE, SEPIA, or AUTUMN LEAVES.

*I also see the normal primary color highlight issues that Sony cameras have where blue highlights go cyan and red highlights go yellow etc. Interesting that particular issue seems to be solved by using REC709(800%) gamma, though it seems to fix the issue simply by clipping off all the highlights where such lights would be an issue... Oddly the issue is fixed in my FS700 by using slog2, but while Slog2 and Sgamut seem to minimize the issue on the A7s, it still exists.

Also I would caution against using Color Depth B+7 to fix the issue as it doesn't seem to remove the crazy blues, only to bring the entire blue channel up to the clipped blue saturation level that occurs in the issue. It will likely make your colors look ridiculous like anything blue is a bright flat blue cutout. In my test, Color Depth just shifted where the issue seemed to appear in the luma and WB range.
 
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Now we just have to figure out if those Clear, Deep, and Light creatives styles are nice enough to be shooting with. Maybe I'll try them out in the field a bit when I get a chance. At first look I think Clear seems too contrasty for me, but Light may have promise.
 
Excellent work, Noah Yuan-Vogel. Adjusting the white balance makes a lot of sense. After all, lower Kelvin temperatures boost the output of the blue channel, and higher temperatures lower it.
 
It also seemed that with B +7, the issue occurred even at very high WB numbers. Color depth is an odd and terrible adjustment, I wish Sony got rid of it.
 
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