How should I deal with green spikes from LED & Fluorescent lights on FS700?

R

rotierney

Active member
I am having some real problems with skin tones when filming in offices/warehouses lit by fluorescent lights on the FS700. I am assuming this is not an issue the camera as I am aware that there are green spikes from fluorescent sources but I need help in finding a solution using the camera's settings if possible. I never had this problem with my 5D MkII or 60D so I haven't had to tackle this issue before. I also get a very green tint from my LED 600 lights with and without a minus green filter, daylight balanced or tungsten. Unfortunately the LCD screen on the camera doesn't really show this much green and my Small HD DP4 has a very warm tint to it so it doesn't show on that either.

I'm using cinegamma 1 with default color settings. Just wondering if there are any tricks of the trade to deal with this issue? Thanks in advance.

Image below is straight from the camera set to 5600K in a fluorescent-lit factory floor.

Green.jpg
 
Try playing with the WB shift in the pp settings. Adjust the CC[MG/GR] and see if that helps. If you praise the level I believe it should help get rid of the green.
 
I white balanced off a white card. Will I get better results using a grey card? I tried tweaking the WB by eye and just couldn't get rid of the green unless I went too warm. I played with the CC too but not too much as I don't trust either the on board LCD or my DP4 to show be an accurate shift
 
It sounds like a process issue more than a white card vs grey (white should work fine, grey may be better, either should do better than what you're seeing). It sounds like you are setting the preset temperature manually, but you also mention that you balanced with a white card so I'm not sure which it is. When you did the shoot what position was the white balance switch in (a/b/preset)?
 
capt chuck said:
It sounds like a process issue more than a white card vs grey (white should work fine, grey may be better, either should do better than what you're seeing). It sounds like you are setting the preset temperature manually, but you also mention that you balanced with a white card so I'm not sure which it is. When you did the shoot what position was the white balance switch in (a/b/preset)?
Click to expand...

I white balanced using a white card with the switch in position A and pressing the custom balance button. In the image above this gave me a reading of 5600K. I sensed there was green so I then manually changed from 5600K up and down but could not improve it so I left it at 5600K. Perhaps I didn't play with the WB shift setting enough but like I said, it is very risky to adjust this too much when you don't trust your monitor. Still having trouble calibrating my DP4 which is proving to be a nightmare!
 
Simply you need to use position B,

-point the camera at something grey/white, press balance button, shoot

A (Temp wheel) adjusts the red to blue ratio of the camera and has no effect on green
 
Here is a very small adjustment in mids and high lights:

Green.jpg

In other words it is easy to fix. But always white balance, I sometimes use a "warm card" (slightly blue card) to get warmer skin tones.
 
morgan_moore said:
Simply you need to use position B,

-point the camera at something grey/white, press balance button, shoot

A (Temp wheel) adjusts the red to blue ratio of the camera and has no effect on green
Click to expand...

Wow I didn't know that. It doesn't mention it anywhere in the manual. Thanks for the tip!

olof said:
Here is a very small adjustment in mids and high lights:

View attachment 58305

In other words it is easy to fix. But always white balance, I sometimes use a "warm card" (slightly blue card) to get warmer skin tones.
Click to expand...

Thanks for that. Yes it's easy enough to fix in post but I would like to get it right in camera.
 
morgan_moore said:
Simply you need to use position B,

-point the camera at something grey/white, press balance button, shoot

A (Temp wheel) adjusts the red to blue ratio of the camera and has no effect on green
Click to expand...

So you are saying that if I color balance with a Warmcard using custom white balance, and the camera momentarily replies that the color balance is set to 5600 K, that the image the camera produces will be different than if I just use the wheel to change to Kelvin temperature to 5600K?
 
morgan_moore said:
Simply you need to use position B,

-point the camera at something grey/white, press balance button, shoot

A (Temp wheel) adjusts the red to blue ratio of the camera and has no effect on green
Click to expand...

I just spoke to a Sony rep and he said that the A and B settings are identical. Interestingly he wants me to return the camera so that they can verify if it is a problem with the sensor. Now I'm really confused!
 
Kraut69 said:
So you are saying that if I color balance with a Warmcard using custom white balance, and the camera momentarily replies that the color balance is set to 5600 K, that the image the camera produces will be different than if I just use the wheel to change to Kelvin temperature to 5600K?
Click to expand...

Yes, it is different. Do neither you or your sony dealer understand colour balance?

Now, I may have been misleading in the button descriptions, I rarely use B

Now with PreSet, it uses a set temperature, and no greem/mag shift*

press the little button next to the switch and you can dial in the preset value

With button A you point the camera at something white/grey and press the little button

The camera displays a temperature value, for example 4800 for a few seconds

This is confusing because it has set the Temp at that value, but also applied a green/mag shift, of a value that it does not tell you or make you aware of in any way.

This is the method you would use to work under lighting with a G-M shift

To get your head round it you could try some experiments

For example point your camera at a green wall, select A and hit the button

The camera will display a value, maybe 4000k, and add a mag shift to equalise out the 'green' cast . the green wall will go grey!

Ponit the camera away from the green wall, you will see a serious magenta shift in the image - you sorted out the worlds biggest green spike!

Now move your camera to Preset and select the same colour temp value, 4000 or whatever it said when you sampled in A mode

Toggle between Preset and A and you will see that they are not the same

B functions the same as A and allows you to store two 'scenes'

-----
nb the menu may give the different buttons different functionaliy so my menu settings may not apply to your camera setup.. but the 'balance off something green test' will enable you to learn what is occuring

S

*unless you have done dialled in in the Picture Profile you are using
 
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Taking it further maybe you are shooting a drama and want a cold feel, 500k under the colour temp, but also to apply a G-M shift to cancel out the GM shift in your lighting. You cannot use the A/sample feature to discover the GM shift as a value, the fact that you cannot discover this is a design flaw in the camera meaning that you cannot go 'off temp', while shooting with low CRI lights, without doing significant experimentation and adjusting the picture profile. such a situation is worsened by the lack of WFM or RGB histo on the camera

S
 
Thanks for your detailed replies morgan_moore. The issue is that I used the procedure you described (with switch positioned to A I pointed at a white card and pressed the little button) but it not compensate for the green in the light. I will be carrying out some extensive tests tomorrow to try to get to the bottom of it and post my findings.
 
I wonder if you have WB set on auto somehow - does it change slowly when you move from a tungsten room to out doors

if it is on auto you turn the camera to a window from a tungsten room and it looks very blue for a few sedons then drifts to white..

S
 
morgan_moore said:
I wonder if you have WB set on auto somehow - does it change slowly when you move from a tungsten room to out doors

if it is on auto you turn the camera to a window from a tungsten room and it looks very blue for a few sedons then drifts to white..

S
Click to expand...

No I double checked that and it was definitely not on auto WB
 
I think the problem you're having is that a color temp setting can not compensate for the unusual spectra of fluorescent or LED lights. Color temperature is a spectrum from red, through white, to blue. So a color temp adjustment will work for incandescent sources -- which are on that spectrum -- but not for fluorescent / LED sources, which are off on another axis.

I would suggest following kcn823's advice and play with the WB SHIFT settings, specifically CC[MG/GR] (magenta / green), which is the other axis. Raise it to positive values to get rid of the green.
 
Have you tried white balancing with a Vortex Media WarmCards 'Minus Green' ?

From http://www.warmcards.com/WC_FAQS.html

"fluorescent lighting usually has a greenish cast to it - thus, distorting colors.
<snip>
Many shooters work under the assumption that a "normal" white balance will
compensate for the green tint of these kinds of lights -- but it does not.
The Minus Green Card counteracts the greenish tint .. "
 
People are spouting total BS of course WB does RB and GM, thats how it works

Balanced off the grey paper
green1.jpg
balanced off the green bag,
green2.jpg
 
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