Sony PMW 200 Blue Colour Cast

[Ramesh Khimasia]

I have just purchased Sony PMW-200 Camera and ran into a problem.

The stage was lit with colour changing LED PAR lights
When the colour changes to blue the whole image becomes ghosty,
all the highlights are replaced with saturated blue colour
When the lights changes back to any other colour the problem disappears
The problem only seems to occurs with blue or purple lights

I have checked with another PMW-200 in the same conditions and the problem occurred in that camera also.

Is it a hardware fault or due to some camera colour settings?

Please guide

[Alister Chapman]

The dreaded blue LED lights strike again. Blue LED's emit intense blue light that is beyond our normal visual range. It effects many, many cameras and may actually be harmful to our own vision.

It is such a big concern that some actors are refusing to work under LED lights as they are concerned (and it is a real concern) about damage to their eyes from the intense blue and far blue light that we cannot see.

[Jack Zhang]

I had to work in a similar situation recently in Seattle, but the intensity wasn't as high since it was a dark room only lit by the color-changing LEDs. I opted to use the BBC Film profile on my EX1R (that uses the "Cinema" Matrix setting which has lower saturation levels) and was careful about adjusting gain and it for the majority of the time didn't clip any channels. (I mostly stuck/fell back to 6db when it started to clip channels at higher gain values)

[Marcus Durham]

Seem this problem many times at events where LED lights are used to backlight the stage. It's really annoying as what looks good to the eye may look terrible on-screen.

Then as you are adjusting the exposure, the blue is so bright you can't expose for the rest of the image.

Sadly this problem will be become more frequent in years to come!

[Ramesh Khimasia]

As the lighting is beyond my control, please suggest best settings to minimize this effect.

[Jack Zhang]

Like I said, an equivalent to the BBC Film profile on the EX1 for the 200 would do. HG2 may be the equivalent to CINE2 gamma on the EX1R (feel free to correct me) and just use a Matrix setting that has less saturation in your picture profile.

[Dean Harrington]

Originally Posted by Jack Zhang

Like I said, an equivalent to the BBC Film profile on the EX1 for the 200 would do. HG2 may be the equivalent to CINE2 gamma on the EX1R (feel free to correct me) and just use a Matrix setting that has less saturation in your picture profile.

One of the other tricks you can do in this situation is use warm cards with the deepest blue card to set your white balance. This has worked for me in such situations.

[Dwayne Parish]

Just wondering if someone can link me to the info of the profiles above. Just got this camera and had this blue blowout problem in a big way on a theatre production whilst an EX1 on default picture profile did not exhibit it on the same shoot. If anyone can link the info that would be great.

[Jack Zhang]

Check out the BBC recommendations for the PMW-200, it has the proper picture profile settings: http://www.dvinfo.net/forum/sony-xdc...ml#post1772288

[Bill Rankin]

If I may resurrect this thread:

Is there any way to 'lessen' the saturation of the blue color only, after the video has been captured? Something that can be done in post that does not involve many hours? In some instances, it looks like shiny blue paint on peoples faces and the floor. Reminds me of Jim Carrey's movie "The Mask".

[Chris Medico]

Originally Posted by Bill Rankin

If I may resurrect this thread:

Is there any way to 'lessen' the saturation of the blue color only, after the video has been captured? Something that can be done in post that does not involve many hours? In some instances, it looks like shiny blue paint on peoples faces and the floor. Reminds me of Jim Carrey's movie "The Mask".

The challenge with trying to correct that problem in post is when you look at the scopes you will see that the blue channel has been clipped. As we know anytime data is clipped it is lost. You can reduce the blue levels with color correction but you will not likely get any more detail from those over-saturated blue areas.

So yes you can bring them down to make them less overwhelming but that won't restore a natural looking image due to the clipping in the chroma channel.

The best tool for the job to prevent this in the future is to have a field monitor with RGB parade waveform. That is a great tool to watch your color saturation and make sure you don't clip a chroma channel. These new LED lights can cause you to clip a chroma channel even when the overall luminance is in range. The normal build in exposure tools of the camera can't handle this situation properly.

Here are a few things to help the situation if you encounter it:
1. Set your white balance artificially high (higher K value). This will reduce the signal in the blue channel and reduce the chance of clipping.
2. In the camera image profile you can reduce the saturation. This can cause your final image to be a bit more noisy when you bring the saturation back up in post so don't lower it more than is necessary to avoid clipping. Going too flat is also a problem.
3. Have a field monitor with a RGB parade waveform so you can properly judge the exposure under these highly saturated conditions.

This will mean you must do more work to restore the image in post but the final image after correction will be better than what you get if you clip.

I strongly recommend getting your hands on some of these lights and do some tests with the settings and tools mentioned above.

[Bill Rankin]

Thanks for the info, Chris. I just want to lessen the 'blue' effect a bit....like I said, it looks like a 'mask' in a few shots. I used Chapman's PP for Asia (I think that's the label) and that made a big difference. Still a bit too blue and sharp, but sufficient. Unfortunately, on the second performance I decided to boost the gain by 3. That was the mistake.


<<<I strongly recommend getting your hands on some of these lights and do some tests with the settings and tools mentioned above.>>>

I went to the dress rehearsal and that's where I learned that the 'Asia' PP of Chapman's would work the best. Next time I'll try to tweak it a bit.

[Paul Anderegg]

Another thread resurrect. I just ran into this blue sheen with my X200 after calibrating it. Saturation has a HUGE effect on that. I ran into the exact same thing even with colors other than blue with my old Varicam, HPX2000, and even my X180, when I put all the vectors in the boxes. Pulling them back always made the issue go away. On my work JVC HM790, the cinema matrix does something similar. I shoot night ENG, so you can imagine how many blue red and yellow intense LED sources at high gain I deal with!

One thing that may also lessen the effect, is to reduce knee saturation if you are on a STD gamma.

Paul