Black Balance - a Black Art?

B

bazza

Active member
I have commented before on the unreliable AWT feature and decided to film an entire wedding without it i.e. using either the 3200/5600K presets or manual WB. Result, all the preset clips have a salmony/pink hue, only the manually set indoor ones are acceptable. Although I often see this in HMC151 clips submitted by others most users seem to think the picture is brilliant so I'm determined to try and sort out why mine isn't. Note: I have already returned one HMC151 which had bad red hue on every shot and this fault was tested and agreed with by the supplier.

I'm now wondering if it could it be the black balance. The manual says it can affect all colour tones but isn't very clear to me how to do it. This may be stupid question but do I point at pure black and hold in the AWB button? How does the camera know I'm not doing a white balance? It says this can be done even when ATW is on, will it be effective for the presets?

The other possibility I can see is in the Setup menu where Ach and Bch color temps can be tweaked. Again the manual isn't very clear as to when these adjustments are supposed to be effective. Can anyone explain them better?

I could spend ages playing with these settings so I'd appreciate any help with understanding what I'm trying to do.
 
Black Balance is all automatic. You don't have to point at anything black, the camera will close the iris fully to prevent *any* light from hitting the sensor. So just hold the button down and let to do an "ABB".
 
OH so doing a black balance, I don't need to point at a black surface? That's what I was confused about.. the manual said a black balance might be needed for brand new cameras or cameras that hasn't been used for a long time.. I was thinking pointing it at a black surface isn't a good way of doing a black balance...
 
Thanks Barry that's useful to know. However I tried it but it makes no difference to my pink hue problem.

I have played around with color temps in the scene menu. I have Ach set to AWT and adjusting the color temp does seem to work when setting but then the AWT is still as unpredictable as ever. I have Bch set to manual WB and adjusting the color temp does work on that too except manual WB wasn't my problem. Adjusting either has no effect on the 3200/5600k presets.

As it stands then I can't even rely on presets but will need to manually white balance all the time.
 
I would set your Color temp A and B channel to 0 before doing anything else,
then do a white ballance /black ballance,
Then check your colors.


Then set your ATW setting to ON in the Auto SW screen.
Then in the SW mode screen, set to A ch

Now test that A channel gives you ballanced color (it should)
In the case it doesn't, only then should you use the Color temp A setting to color correct.

This should work, if it still doesn't then try using warm/cold cards for calibration to your liking.
 
Sounds like you have a little minus green getting in, you should be able to fix this by adjusting the color phase. Are you shooting under house fluorescent lights? Their color temps vary widely and it is hard for a camera to white balance to them.
 
Bazza:

I would call getting a pink hue during weddings a common issue. With the white dress and lots of other white, combined with the indoor nature (and lighting) of at least parts of the wedding, you tend to see all of the color shifts you don't normally notice.

The ATW will work pretty good outside, but go inside, especially a white tent like a wedding reception might have, and it will not be able to handle it at all.

A single good MWB in each venue of the event is all I would do. Too many MWBs will have the color all over the place.

In post, color grading is just a part of the editing process IMO. Absolutely every shoot, with any camera, needs it.

Most NLEs have a primary & secondary color corrector that is somewhat automated, so it's not too big an issue, usually.

However, having the camera exposure and color as accurate as possible makes a much better image as it is processed at a higher bit rate versus NLE editing at 8 bit.
 
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