modded camera white balance

[Rigel003]

I've just had my Canon 6D modded with a Baader BCF2 filter replacement. I understand that I can use it for regular daylight photography by setting a custom white balance. For astro imaging though, should I also use the same custom white balance during capture rather than correcting the red cast in post processing?

[Merlin66]

No, don't use the CWB during astro imaging...

You'll only pick up the enhanced red emission wavelengths if they exist in the object being imaged ie Ha in Nebulae etc. Otherwise they will be pretty "normal"

[luka]

I thought that the white balance is only applied to the JPG files and not to the RAW files. As you should be using RAW for the astro imaging (JPG compression will degrade images) it does not matter which white balance is set in camera.

Someone please correct me if I am wrong.

[Merlin66]

Luka,
I don't use it, so not confident of its use.
http://www.properproof.com/digital/Digital%20Assignments/White_Balance/custom_wb_canon_rebel.htm

But in the manual p90 it doesn't say it can't be used with RAW files.......

[Rigel003]

Ok, thanks. I've since read that if you're capturing in RAW that the WB set in camera makes no difference to the file. However I usually capture in large jpg at the same time and it would have been nice to get a sense of the images with proper colour balance in the preview screen.

Not sure I understand the point in your first post though Ken. Surely the modded filter allows the sensor to capture Ha emission that couldn't be captured before, but that doesn't mean that everything in the frame needs to have a red tinge.

[ErwinL]

Adjusting the WB will remove the red tinge not only on the additional JPEGs but also on the JPEGs which are embedded in the RAWs and therefore also on the camera display.
And yes, the suppression of the reddish look will not reduce the red channel resolution. It's just the opposite: The original loss of red in an unmodded camera is compensated by multiplying the red channel by about 2.5x. This should(!) be ommited after filter removal.

[Merlin66]

Graeme,
""
rather than correcting the red cast in post processing""

In response to the above I was trying to say, if there's no red Ha emission then there will be no red in the image and no red cast to correct..