A7S Serious "Colour Burn" Problem

S

Simon Shasha

Well-known member
I wasn't really sure what to title this post. I'll let the pictures I attach speak for themselves.

I filmed a concert on Friday (12th September, 2014) using my A7S in APS-C mode with a Sony E-Mount 35mm F1.8 and Sony E-Mount 50mm F1.8.

I filmed in S-Log2, ranging between 3200ISO - 12,800ISO, with a white-balance of 4500K (sometimes I'd go to auto white-balance to deal with the speed of the constant changing lights).

From the beginning of the night, I noticed the image would somewhat "burn" when the stage lights would peak to a certain brightness and reflect on surrounding objects and people. I hoped that maybe this what just my camera's LED and not how the final image would look once viewed on my PC. However, turns out my hopes were in vain and a lot of my shots were ruined.

I'll attach a "before and after" shot below to give a general idea of what I'm talking about. Now, I'm not sure if this is a user error on my behalf (I don't think it is because a friend of mine who just shot a night-club in Bali with his A7S experienced the same problem), or if it's a short-coming of the codec/8-bit S-Log2...?

If this can be fixed via a firmware update, I'll gladly take it as I love the image I am getting from the camera in general. If not, then I'm not sure what to do. I doubt Sony will refund for this? A lot of my work is night-club/concert work - I wouldn't be confident using the A7S again knowing it's going to "colour burn" a lot of my images...

I'll also throw this in - I had my GH4 set-up on a tripod at the back of the concert filming in 4K (25FPS) at 800ISO with CineStyle-D (with colour and saturation set to -5) all night. The image is absolutely perfect. Really beautiful. No "colour burns" or anything - even when the stage lights peaked at their highest. Was very surprised and impressed by GH4's performance.

Anyway, here are two shots taken about half-a-second apart:

C0055 (0-00-06-39).jpgC0055 (0-00-07-27).jpg
 
Although I haven't seen this myself, I still wonder if a uv filter on the lens would help. LED lights are all very strong at the UV end of the spectrum. Cheaper LED lights leak stray unfiltered UV light.

I noticed that the A7S sensor is well filtered for infra red, but I wonder if the other end of spectrum is not so well protected.
 
I don't have a UV filter to try that out, but anyone finding a solution will get lots of love from event videographers.
 
You said the GH4 performed impressively but to be fair it wasn't recording at anywhere near as high an ISO as the A7S did. The A7S wouldn't have any problem with strong LED light at ISO 800 either.
 
I solved this Blue clipping problem by going into the picture profiles, Color Depth, and turning B up to +7.

Nobody else seems to have tried it, so it would be nice if someone would and report back.
 
Those kinds of LED lights look even worse to my eyes in real world. They should be forbidden. I hate venues with LED lights. I hate watching performances lit by LED lights. When I have to film it I hate them even more.
 
Well those lights are here and people use them so we have to get this fix, but doesn't look like they will since their high end camera is like that too and also the Red but I hope Ralph is right that you can fix it by turning up B value to 7, I was using Canon Mark 3 and never ever have this kind of problem.
 
I hate this Sony issue . Please do not tell me that other brand camera has the same problem . NO ,never saw with Canon or Panasonic . SONY JUST SONY !!!!!!!!
 
See the thread about 'colored highlight peaking' for more info on this. Looks like there are a few creative styles that help the issue and it looks like whitebalance is a big part of it. Blue color depth does have a role but I don't consider that the best fix. Use clear, deep, or light styles or avoid low white balance numbers. And definitely complain to sony support.
 
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