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View Full Version : White Balance for Dummies



morgan_moore
07-13-2011, 02:53 AM
OK how do you control WB on this little thing?

What I reckon is happening..

Preset - uses the temp you have set in the menu

A - goes to an unkown to me value

B goes to an unknown to me value

apparently the same

Pres the WB button and it samples what you are pointing at

Once the WB button is pressed the switches do nothing

If the camera holds this value with removal of battery etc I dont know

Also Im not finding the 'Drifting WB faciliy' which while generally avoided could be of use for example transitioning from a Daylight EXT to a Tung room

-----

I have Flouro and Tungsten lights and gelled T too

I would like to point one of these at a white wall (lit with Tung source) and press WB to sample it - I would then like to save that as 'my tungsten'

and repeat with 'my flouro'

And Shade and Sun ?

Maybe Id then like to tweek the sampled settings to create my own feels like 'Flouro Warm look' or "cold under tungsten"

What is the approach people are taking

One thing I want to be able to do (especially in my studio) is get consistency between Monday and Thursday - even if I shot something else on Tuesday in a different locaton

Currently the only one of value seems to be a setting in the menu - but thats a bit clunky and would need notes if shooting over days also it is a complex rejig in the menu to compensate for flouro which might be a bit green and needs a magent swing and that cannot be done on the temp scale - but in the PP menu

TIA

S

morgan_moore
07-13-2011, 03:05 AM
Also PP1 can I rename that to somthing like 'TungGelled' or 'HighDRSunnyDay' (as per EX1)

S

SergeSmArt
07-13-2011, 03:55 AM
OK how do you control WB on this little thing?

What I reckon is happening..

Preset - uses the temp you have set in the menu

A - goes to an unkown to me value

B goes to an unknown to me value

apparently the same


As far as I've got it .. I have to set OUTDOOR WB and this will be A .. and INDOR WB ( I took a shot of White paper ) and it will be B .. than I can switch between them .... and I can use simple Kelvin temperature to make my own WB ...

speedracerlo
07-13-2011, 04:05 AM
I had some problems with White Balance Memory A and B giving off some odd color cast.
If I use the Memory A or B to set the white balance and get a reading of 5000k and then I switch to Preset to manually set the white balance temp to 5000k, it looks different from the Memory A or B reading of 5000k.
I'd stay away from using A or B setting until this color cast thing is understood. Someone else please verify.

morgan_moore
07-13-2011, 04:07 AM
Aha the mystical >[]< button

Press to sample

So outdoors Ive sampled a white card and it picked 6000 or something - thats now A

and indoors I pointed it at a light and it picked 4000 or something thats now B

But it doesnt tell me those values

So useful ish in a RnG situation but not so good to go back to

A good start thanks

S

stevedocmaker
07-13-2011, 03:33 PM
There is definitely a difference between balancing off a grey card (usually more acurate than a white card BTW), and setting the color temp manually. This is very irritating, as it shouldn't be the case. As soon as I have a chance I'm going to play around with the white balance adjustments in the picture styles and see if there's a way to get these methods to synch up. BTW, to my eye the manual input method yields a slightly warmer tone, and I think the grey card is more acurate, at least under daylight. This may not be the case with multiple light sources.

morgan_moore
07-13-2011, 03:55 PM
My guess is that selecting a temp in the menu alters the R->B spectrum ie the colour temp

Lets say you WB (using the click facility) off a Flouro (green) not only with the R->B spectrum be altered but the 'tint' (as still photogs call it) ie the Mag->Green Spectra

The M->G spectra can be fiddled in the menu of a picture profile

Considering the speed of just clicking on a grey card it is a shame that that cannot be stored in a way that is can be recovered or named or evaluated .. (as far as I know)

For 'serious'/repeatable work work it would therefore seem that it is a question of building picture profiles manually

The fact that these proliles dont seem to be possible to have titles assigned to them is another step backwards from the EX1

Oh well

S

morgan_moore
07-13-2011, 03:59 PM
I suppose what I want is to get profiles that are based around my key light source

For example I might make
Kino - True
Kino - Desat cold
Kino - warm and fluffy

GelTung - True etc etc

These would be created from my actual lights

S

morgan_moore
07-13-2011, 04:02 PM
(usually more acurate than a white card BTW),.

My general method say with a Kino is to fill the frame with it (maybe using an expo disc to defuse) stop down until the frame is at 60% grey and then click the auto facility

Logical?

S

bkmvincent
07-13-2011, 04:04 PM
My general method say with a Kino is to fill the frame with it (maybe using an expo disc to defuse) stop down until the frame is at 60% grey and then click the auto facility

Logical?

S

I was taught to use a white card and not shoot directly at the light source, but maybe that's not correct? Not sure, I've always used ENG style cameras and the WB button has always yielded very good results. However I have had trouble with Diva's in the past giving a slight color shift.

morgan_moore
07-13-2011, 04:17 PM
Ive just been testing by filling the frame with a green plastic bag... to replicate an extreme green light source

Now auto wont correct it

Nor can the color temp wheel (as expected)

But if you go to A or B and press the >[]< button it does make the bag go grey (and the rest of the room a wild magenta!)

I would conclude from that that the best method, without in depth use of a picture profile is to

-Fill the frame with your light source

-Hit >[]< and save that source to A or B

This will give a 'true' R-G and M-G grey from your source

Should you want to create a looke like "Kino Warm" the operation should be done with a mild blue filter over the lens (Expodisc make such items)

Such a process should be reasonable repeatable

S

morgan_moore
07-13-2011, 04:21 PM
I was taught to use a white card and not shoot directly at the light source, but maybe that's not correct? Not sure, I've always used ENG style cameras and the WB button has always yielded very good results. However I have had trouble with Diva's in the past giving a slight color shift.

I would agree that a more correct method, but less practical on set, would be to point the light source at a grey card

I think such a method would be particularly true for small specular sources (like HMI or hot lamps fresnels etc)

I think my method is probably 'OK' for the soft sources I tend to use

One WB method I have never understood is taking a WB of ambient or master light - if there is for example a talent in a red jumper that is obviously going to throw the reading

In reality I usually balance off my white van outdoors or a bit of foam core board that may be lying around indoor, stopeed down a couple to make sure there is no channel clipping

S