Color Balance with H-alpha mod

I had my Sony A7S modified for H-alpha by lifepixel, but did not have much chance to get out under dark skies.

Anyways, after some health issues, I am out in the field and cant figure out the best approach to white balance?

Foreground shots ? Sky background? I do not want to rely on color balance in post for stills later – does not always work out well, even in raw.

Help help, can you recommend the best approach at night?

-- Rick

Have an Baader astromodded Canon 6D (modded by Canon in Germany).

Use daylight white balance for the night sky. Subtract some red for the landscape part. But then I am not going the full mile when it comes to those last natural colored rays.

Astromodded cameras are superb for rich (did not say natural) sunsets!

Guess post processing play a big part here. In my case the basics are done in AstroArt and the rest in Photoshop - work well inn my case.

I'm also looking into a modded camera from Lifepixel

I just can't decide, nor do I really know the difference between a full spectrum conversion and an H-alpha conversion.

I'm looking to buy one of their camera's already modded, so it will be dedicated to night photography.

I am one of those that generally shoot in light polluted skies with just a DSLR and a tripod. Sometimes I'm able to get to a dark sky site.

Make sure you have a plan for full spectrum. You will end up spending a lot of money on filters !!

When I use daylight white balance, everything looks pretty red in the monitors?

Tried custom white balance but difficult at night ....

rick colman said:

I had my Sony A7S modified for H-alpha by lifepixel, but did not have much chance to get out under dark skies.

Anyways, after some health issues, I am out in the field and cant figure out the best approach to white balance?

Foreground shots ? Sky background? I do not want to rely on color balance in post for stills later – does not always work out well, even in raw.

Help help, can you recommend the best approach at night?

-- Rick

Click to expand...

Do you have a full spectrum mod? Or is there an internal IR/UV filter?

Mark

--
Takahashi Epsilon 180ED
H-alpha modified Sony A7S
http://www.markshelley.co.uk/Astronomy/

rick colman said:

Make sure you have a plan for full spectrum. You will end up spending a lot of money on filters !!

Click to expand...

So if I get full spectrum, I'll need a filter as well? All the time, or just during the day?

If I get the H-alpha, will I need a filter?

rick colman said:

I had my Sony A7S modified for H-alpha by lifepixel, but did not have much chance to get out under dark skies.

Anyways, after some health issues, I am out in the field and cant figure out the best approach to white balance?

Foreground shots ? Sky background? I do not want to rely on color balance in post for stills later – does not always work out well, even in raw.

Help help, can you recommend the best approach at night?

-- Rick

Click to expand...

Get a photographic grey card I think its called an 18% photographic grey card (a neutral grey cardboard card).

Using the custom white blnce feature of your camera take a photo of this card in sunlight around midday. Now set that photo as your custom white balance and it will correct the overly red photos you are getting now.

Greg.

Astrophotographer 10 said:

rick colman said:

I had my Sony A7S modified for H-alpha by lifepixel, but did not have much chance to get out under dark skies.

Anyways, after some health issues, I am out in the field and cant figure out the best approach to white balance?

Foreground shots ? Sky background? I do not want to rely on color balance in post for stills later – does not always work out well, even in raw.

Help help, can you recommend the best approach at night?

-- Rick

Click to expand...

Get a photographic grey card I think its called an 18% photographic grey card (a neutral grey cardboard card).

Using the custom white blnce feature of your camera take a photo of this card in sunlight around midday. Now set that photo as your custom white balance and it will correct the overly red photos you are getting now.

Greg.

Click to expand...

Yup. That's the best starting point. You will likely still need to do adjustments in post to get rid of gradients from light pollution and perhaps some overall color cast from terrestrial sources, but that should, at least, get you a decent starting point for a neutral night sky with a camera that has no IR cut filter.

I have/had two moded camera bodies: pentax K-1 full spectrum and Sony A7S h-alpha

The Pentax required a filter on the lens at all times, depending on the desired light s-pectra. No filter means the sensor responded from near UV to visible to middle IR; which is basically useless as far as I can tell. Forget full-spectrum for me, at least.,

The Sony mod (lifepixel) is supposed to enable the sensor to respond from visible through H-Alpha and Sodium.

So my question, with answers not understood, is I want the "sky part" of my image to show the enhanced red response, and I want to ground/foreground to look natural.

I would like a viewer to say, wow, great sky and natural landscape below. I don't want the sky to look "unnatrually" red whatever that means.

I have the ground part down OK, but don't know how to color balance for enhance J-alpha on the sensor.

Jared Willson said:

Astrophotographer 10 said:

rick colman said:

I had my Sony A7S modified for H-alpha by lifepixel, but did not have much chance to get out under dark skies.

Anyways, after some health issues, I am out in the field and cant figure out the best approach to white balance?

Foreground shots ? Sky background? I do not want to rely on color balance in post for stills later – does not always work out well, even in raw.

Help help, can you recommend the best approach at night?

-- Rick

Click to expand...

Get a photographic grey card I think its called an 18% photographic grey card (a neutral grey cardboard card).

Using the custom white blnce feature of your camera take a photo of this card in sunlight around midday. Now set that photo as your custom white balance and it will correct the overly red photos you are getting now.

Greg.

Click to expand...

Yup. That's the best starting point. You will likely still need to do adjustments in post to get rid of gradients from light pollution and perhaps some overall color cast from terrestrial sources, but that should, at least, get you a decent starting point for a neutral night sky with a camera that has no IR cut filter.

Click to expand...

rick colman said:

I have/had two moded camera bodies: pentax K-1 full spectrum and Sony A7S h-alpha

The Pentax required a filter on the lens at all times, depending on the desired light s-pectra. No filter means the sensor responded from near UV to visible to middle IR; which is basically useless as far as I can tell. Forget full-spectrum for me, at least.,

The Sony mod (lifepixel) is supposed to enable the sensor to respond from visible through H-Alpha and Sodium.

So my question, with answers not understood, is I want the "sky part" of my image to show the enhanced red response, and I want to ground/foreground to look natural.

I would like a viewer to say, wow, great sky and natural landscape below. I don't want the sky to look "unnatrually" red whatever that means.

I have the ground part down OK, but don't know how to color balance for enhance J-alpha on the sensor.

Click to expand...

Finally you answer my earlier question which was:

rick colman said:

rick colman said:

Do you have a full spectrum mod? Or is there an internal IR/UV filter?

Click to expand...

Click to expand...

So I now have enough info to answer yours.

I use a modified A7S. It's a full spectrum mod which means I must use it with a IR/UV filter. Sounds like your modification cuts out most of what is beyond H-alpha and Sodium - which is good. So it will be similar to my IR/UV filter.

The H-alpha mod allows 4x as much H-alpha to be recorded. But for broad spectrum emitters (like our sun) the mod ends up letting twice as much red light through. So I find I must "dial down" the red channel by a factor of 2. This makes sunlight look white and by doing so will also give a natural colour to all other stars. A custom white balance will have a similar effect (of dialling down the red). H-alpha emission nebulae will still be twice as bright as before, even when the red channel is dialled down by 2. So the landscape can look natural, the stars look correct and the emission nebulae look enhanced, all with the same colour balance.

That's the approach I take.

Mark