Urgent help needed with colour problem

S

sargo

New member
Hi there,

I hope somebody can help me! I bought the FS100 last week so I could test it for a short feature documentary I'm shooting in September. I took the camera to Finland to shoot the same band I'm shooting in Russia next month. I'm mostly over the moon with the quality and ease of use...BUT I noticed a colour screw up that I can't seem to fathom....but really need to find a solution to. When the lights turn to deep blue the highlights (I think) seem to turn black....it only seems to happen with blue light as you can see, a really similar attached red pic is fine. I was using G-LOG A most of the time but when I noticed the problem I actually ran through the whole profile list and though the hue changed the problem didn't.

I know P Bloom has posted a very similar issue (the same) there seems to be no explanation....It's something I need to get some kind of solution to as approx 1/3 of the show is this colour and it'll rule out heaps of footage if I just don't shoot when the blue lights are on! If Frank Glencairn is reading I'd really appreciate any suggestions....This is a pretty major film for me and the band.

Many thanks, Sargo.

NB. The blue pic attached is actually a pretty mild example.
 

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The Sony FS100, FS700, F3, etc have significant issues with primary red and primary blue highlights and usually red turns yellow and blue turns cyan both pretty suddenly, however I've never seen that black problem. I have seen that problem appear in footage turned black and white, since it seems that that color shift when turned black and white becomes a shift from white to black. I have not seen primary color highlights turn black in color footage though. I've seen digital cameras have issues with overloaded pixels turning black such as when shooting the sun or other very bright things but that does not appear to be what is happening here since the part that turned black is not the brightest part, it is the slightly less bright part of the lights just outside of the brightest part of the light...

What is your picture profile? I'd see if you can reproduce the issues and then play with settings to see if you can fix it, especially trying different gamma curves and color modes.
 
It's jsut result of over-exposure and too much contrast in the scene.. :) I had it once with FS-100:

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Don't know if it will be the same with my current FS-700.. but I don't think so..
 
I have seen this on my CANON 7D so its not a camera specific issue

--

Its tricky lighting - Led seems to do wierd stuff

I dont know the answer but to test some profiles, and then maybe some different cameras.

Id stick knee at 105 for starters and black level high +7

I also wonder if it is IR or UV messing with the sensor, you could try filtration of same.

Far out.. You could cut the blue light levels hitting the sensor by adding a red (coloured) filter and compensating with colour balance.

You could try and get the lighting designer to lower the DR in the scene by adding a white wash or turning down the intensity of the lights in blue mode - I guess they are all driven by some sort of computer

The wash could be a follow spot on the talent allowing you to stop down or use less gain or maybe a few fill lights (flashing in time with the lighting design so the dark moody bits are still dark) down by the floor monitors at the front of the stage

You might also try adding some gels to the lights, UV, IR etc

Dont forget - it is the band who want a result as much as you, or more, so a team effort is not out of the question - in my early days shooting stills for NME I used to have the no flash thing making photography impossible with some lighting designs (this was the rave era), I used to point out that It was them, the band, not me, that needed the publicity, soon they allowed my flash, maybe it compromised hte audience experience at the gig by 5% but it allowed them the large audience of the readership of the paper.

Positively engage with the crew and make them feel that the film is a mutually beneficial experience.. I mean the lighting designer doubtless wants a great showreel.

I also note that the skin is blown on the talent, so why not stop down until at least the talent is correctly exposed.

S
 
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It could indeed be just because they chose to use LEDs... I was watching a live kids show on national tv, and they used LED Pars as well. Even with broadcast cameras, the light looked like ****, banding and turning black here and there.

Have you tried looking at those x-mas LED light chains? You can't really focus on them with your naked eye.... they are just messed up.

About what to do about your footage. I'm not a hardcore grader, so I honestly don't know.
 
I think the OP is testing for future shows (wise man) so getting it right before shooting is possible..

although some form of post solution may be possible

I do the eden sessions most years, which is always filmed (and therefore I guess lit for filming - EX3s), they have a tungsetn follow spot on the talent which works so well that photography and filming is effortless

S
 
I personally never run into this (but I don't do disco) but I#m aware of the problem.
It's those sh...y LED crap. I avoid this stuff like the plague, but sometimes you have no option.
A combined infrared/UV filter might help, but that's just a wild guess. (You should have one anyway on your FS100/700).

Hard to say anything without having such an LED par here and doing some tests.
For starters I would +1 what Morgan said, crank your knee up and give it a testride - also lowering saturation and playing with the color levels may help.

I think, I'm not much help here, sorry.

Frank
 
Hello everybody, thanks so much for all the replies and opinions, it's great to have a community of folk to talk things over. I've tried to emulate the lighting at home and had similar results, but only with the deep blue/purple gels. It's really annoying!! I've done the same test with my 7d and a couple of Nikons and it's only the Sony that looks anything like this....seems like a pretty major fault (to me at any rate) I wonder if it's correctable with software of some kind....I will try all the suggestions (Thanks Frank for your thoughts) and let you know.

Cheers, Sargo.
 
I've seen it happen before with LED lighting. Some camers are more sensitive to it than others. If I can find it, I'll post a link but I did come across a document on the web that went into the limits of shooting LED lighting and had recommendations for the maximum intensity for each colour before it would overload the sensor. Of course you'd need to refine those limits for the FS100.

The idea would be to talk to the lighting designer, do some tests, and get them to program those limits into their desk. If that can't be done, then you may need to pick a different camera for that particular job.

If you search these forums you'll find plenty of LED stage lighting horror stories with pretty much any CMOS camera you care to name.

Personally, I could almost live with the inverted highlight. Compared to some of the things that cameras can do under LED lights, this one is at least fixable in post.
 
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I shot under LEDs with a T2i and I ran into problems, mostly with flickering, but I did get some of the black blobs on some shots and some really strange motion artifacting. I don't care for LED stage lights at all. Hats off to the OP for doing his testing.
 
Jeff Kirkland said:
I've seen it happen before with LED lighting. Some camers are more sensitive to it than others. If I can find it, I'll post a link but I did come across a document on the web that went into the limits of shooting LED lighting and had recommendations for the maximum intensity for each colour before it would overload the sensor. Of course you'd need to refine those limits for the FS100.

The idea would be to talk to the lighting designer, do some tests, and get them to program those limits into their desk. If that can't be done, then you may need to pick a different camera for that particular job.

If you search these forums you'll find plenty of LED stage lighting horror stories with pretty much any CMOS camera you care to name.

Personally, I could almost live with the inverted highlight. Compared to some of the things that cameras can do under LED lights, this one is at least fixable in post.
Click to expand...

Thanks Jeff, that's a good idea, especially if I can give the lighting guy some idea of levels to avoid, everything else has been amazing with the FS100. I'd really appreciate the link if you find it. I'll post some samples on my Vimeo channel as soon as I get approval from the bands management. I've included a couple of shots with the "black in blue" problem but you have to know they're there to see.....I did try and grade some bad ones out but with little success I'm afraid.....weird that it's just blue!? I won't pretend to be any kind of expert in these sort of things, like a lot of working shooters out there I rely on the great people on forums like this! Thanks again.
 
Tell 'em it's a feature and move on. Like lens flare, only (slightly) different. Really, are people going to be looking at the lights in your video, or the people in the band? They certainly aren't going to be looking at stills -- if the see this at all, they'll see it go by in motion.

But if you're determined to eliminate the problem, first thing to do is find a way to recreate it where you can play with it. And the first thing I would try would be a combined IR/UV filter. Next would be a light yellow (AKA minus blue) filter like is used for B&W film photography. Why? Well, it's not like color accuracy is an overridding concern here, and if it's overloading the blue channel that's the problem, lessening the amount of blue might just be the cure (you can always turn the blue back up in post). If this works, you'd need a way to get it on/off the lens in a hurry (and of course adjust your exposure accordingly) and possibly some coordination with the lighting guy so you'd know what was coming (radio coms?).

But if you can't recreate the problem under controlled conditions, you'll just be guessing. Like I am now. ;-)
 
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