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Modified Canon white balance !

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#1 bouffetout

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Posted 08 December 2012 - 12:50 PM

When I take my astrophotos with the Canon T3 the whit balance is set on the sun icon ,that's what I was told to do.
Now that my T3 is modified ,do I take a photo of a white sheet
on that icon or I make a custom one ? All I have to do for
white balance is take a photo of an equaly lite white sheet?
I don't have to play with the histogram ?
Thank you !
Maxx

#2 Footbag

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Posted 08 December 2012 - 02:21 PM

I shoot in RAW and use Deep Sky Stacker to process, so white balance is irrelevant in my case because it is ignored. I then correct color in post processing.

If your stacking software doesn't ignore it or you are shooting JPG's, then you could take a picture of a true white sheet of paper on a sunny day. Then use that as a custom white balance.

#3 bouffetout

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Posted 08 December 2012 - 02:54 PM

I shoot in RAW and process in Deep Sky Stacker too ,so
I don't need a white balance ,work will be done in processing.
That's simple enough :grin:
Thank you dude !
Maxx

#4 waassaabee

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Posted 08 December 2012 - 06:58 PM

I've always used a Custom White Balance as it makes the color balance a lot simpler in post process.

#5 bouffetout

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Posted 08 December 2012 - 07:09 PM

Thank you my friend ! The opinions seems to vary a lot on that topic from what I read in other forums...I guess I will
have to test the two ways !
Maxx

#6 achronut

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Posted 08 December 2012 - 11:51 PM

Please correct me if I'm wrong. White balance is supposed to correct how an object appears when it is illuminated by ambient lighting. So in a dark environment, a dark background sky for example, there is no ambient light. And the objects (stars, etc) ARE the source of light. So WB of astro shots may be greatly affected.

I shot a white paper using my modded 350D under direct sunlight and used this as the initial CWB. However, my shots of M33 turned out more on the green side. Obviously the WB was way off.

I experimented further and used that initial WB setting to shoot the same white paper in a room illuminated by fluorescent lighting. The resulting image i then used as final CWB. My M45 shots' WB appeared well-corrected by this final CWB setting. Only a little tweaking of WB is required in IRIS and in PS.

#7 Magellan

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Posted 09 December 2012 - 12:30 AM

I always use CWB, using a white sheet or gray card. I tell DSS to use camera CWB. I find I get better color this way.

#8 nofxrx

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Posted 09 December 2012 - 05:12 PM

If you shoot Raw, it makes ZERO difference what WB setting you used.
WB has ZERO effect on the actual data you collect...
However, I find I always get the best results leaving the camera set to CWB(the same CWB I use for DAYTIME!), having DSS/whatever SW you use to select the WB used during capture for processing. This usually gives me an easier color balance to deal with in post processing..
Again, however....who cares? your color balance(WB) is EASILY adjusted in post processing anyways using levels or curves in PS...so if you are going to process your images to your liking, who cares which WB you use.
If you dont, keep it set to either AWB or CWB.
Never set a modified camera to anything other than those two settings. imho.
And AWB is going to be useless for daytime..obviously. but for AP, again, who cares?

Hope this help :)

Cheers

#9 nofxrx

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Posted 09 December 2012 - 05:24 PM

Oh, for taking a CWB, easy:
1) Set camera to AWB
2) Take a white/18% gray card outside, on a NICE SUNNY day! mid-day is best
3) Set camera to Av mode
4) set lens to MF, focus at infinity(just helps keep the image completely flat)
5) Set aperture to F/8
6) take image so that there is a nice flat image, with no shadows from the camera/lens is not visible, etc
7) go into the menu and select CWB, the camera will pull up images on the memory card that are suitable for use. Select the image you just took, and click "OK"
8) Set camera to CWB
DONE!

This is perfect for any STANDARD modified camera..meaning an IR Block is INside the camera!
This will work for 99% of your lighting situations, even indoors..
I have used this kind of CWB for years for PAYING photo and video work! if it is good enough for the toughest clients, I think it will work fine for most casual shooters/APers!

Cheers!

#10 bouffetout

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Posted 09 December 2012 - 05:51 PM

Very good explanation ! All I needed to know is there...only one detail ,I use a clip-in CLS filter in my camera ,do I shoot with it or not ?
Thank you very much sir !
Maxx

#11 nofxrx

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Posted 09 December 2012 - 05:55 PM

For creating your CWB?
yes. I would.
But again, shoot WITH the Filter, but use AWB to take the image you are going to use for the CWB...this SHOULD solve most if not all of your issues.

Everyone/camera/setup/location is different...but maybe this will help somewhat, or atleast get you on the right track.. :)

#12 bouffetout

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Posted 09 December 2012 - 07:21 PM

Perfect !
Thanks again !
Maxx

#13 nofxrx

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Posted 09 December 2012 - 07:32 PM

Not a problem! I hope it helps! :)
Also to note, you do NOT need to keep this CWB image stored on your memory cards...as soon as you tell the camera to use that image for the CWB data, it stores the image DATA in the camera's internal memory, it does NOT need/use the memory card for the CWB from this point on.
And it will be permanently stored inside the camera UNLESS you: restore to factory defaults, or load another CWB..

good luck!

#14 bouffetout

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Posted 09 December 2012 - 08:38 PM

You did help a lot !
Thanks again !
Maxx Brodeur
No wife and two loving cats ;)






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