Go Back   IceInSpace > Equipment > Astrophotography and Imaging Equipment and Discussions

Reply
 
Thread Tools Rate Thread
  #1  
Old 13-02-2006, 08:39 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
White Balance in Astrophotography (with Modified 300D)

Hi,
As many of you are aware I have recently modified a couple of 300D's for use as astrophotgraphic cameras (Removing the internal UV/Ha-IR filter).
This has made me ponder a couple of questions about white balance....

When shooting in Jpeg the white balance is determined by the WB setting. And for astro work I have always left it on Auto, so God knows what white balance has been applied! One would argue that for an astrophoto that is going to be processed etc, no white balance should be applied at the camera. However there is no setting for NO WB!
Even when you use the RAW format, as soon as the Canon software converts these files (to tif, or jpeg ect) the WB info is gleened from the EXIF data associated with the RAW and applied!

So, my questions still remains.... How do you get a NO WB image from the 300D????
I haven't done any web hunting on this topic, but perhaps there is a way to convert RAW to TIFF without WB adjustment...

Thoughts & discussion?
Cheers

Last edited by Robby; 13-02-2006 at 12:15 PM.
Reply With Quote
  #2  
Old 13-02-2006, 08:56 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
I've just been playing around with a RAW file in Canon Digital Photo Professional and with RAW files you can apply all sorts of WB, but not NONE... Am I missing something? Surely there must be away to get the direct data out of a RAW file without any sort of WB correction???
Reply With Quote
  #3  
Old 13-02-2006, 09:11 AM
acropolite's Avatar
acropolite (Phil)
Registered User

acropolite is offline
 
Join Date: Feb 2005
Location: Launceston Tasmania
Posts: 8,988
Robby, There's a raw plugin for photoshop and you can select "As Shot", which one would assume is no correction. The plugin also has a slider for balance so you can easily apply whatever balance suits your taste...
Reply With Quote
  #4  
Old 13-02-2006, 09:16 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
Hi Phil,
Canon Digital Photo Pro also has the "as shot" setting....
From what I can tell the "As Shot" setting applies the WB that the camera was set to at the time of shot. Eg. If the camera was set to "Flash" WB then the "As Shot" setting will apply "Flash" WB compensation to the RAW file.
Cheers
Reply With Quote
  #5  
Old 13-02-2006, 09:55 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
Ok,
I think I have worked it out.....
Using ifanview and the CRW (canon raw) plugin. You can un-tick a box to not use camera white balance.
I took 2 shots with the 300D, with different WB settings. When I open these RAW shots in ifanview they are identicalm implying that no WB has been applied. I can then save in Tiff.....
Ok, this has been my own little blog tread but I hope it helps someone!
Reply With Quote
  #6  
Old 13-02-2006, 10:28 AM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,680
no mate conversation with your self are healthy .

great information, where did you find the program/info? whatever you di i will be sure to follow .
Reply With Quote
  #7  
Old 13-02-2006, 10:34 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
ifanview is a freeware image viewer/converter that I have used for ages for basic image viewing
Get it from http://www.tucows.com/preview/194967
Then get the plugins from http://www.tucows.com/preview/415586
Then run ifanview. Find the plugins setting box, and untick all the boxes associated with white balance!
Easy!....
Only problem is, is that it's yet another step in the image processing process! I may continue to stick with AWB (auto white balance) as the differences between AUTO & NONE seem very minor!
Cheers
Reply With Quote
  #8  
Old 13-02-2006, 10:38 AM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,680
Thanks Robby. Looking forward to this next few weeks, more testing of the camera and settings! Will see how to apply the WB settings in camera and see what difference is made on same target, same settings
Reply With Quote
  #9  
Old 13-02-2006, 10:46 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
I stand corrected... There is quite a big difference (in daylight at least) between AutoWB and NoWB..
First image is with AutoWB applied. Second is with No WB applied.
Be interesting to compare night time shots....
Attached Thumbnails
Click for full-size image (CRW_5285_AWB_web.jpg)
55.9 KB18 views
Click for full-size image (CRW_5285_NOWB_web.jpg)
59.1 KB20 views
Reply With Quote
  #10  
Old 13-02-2006, 11:25 AM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
Right,
I'm putting this one to bed......
The closest 300D white balance to have no white balance is the "cloudy" setting. There are very small differences between having NoWB and having a CloudyWB.
It probable that AutoWB will use this setting at night anyway, so this excercise has been pointless.....

So my recomendations for White Balance for Astrophotography with the 300D...
1. If possible use None (convert using ifanview as above)!
2. If your like me and a bit lazy, then use the "cloudy" WB setting as it is the closest to using none. I'm not sure I trust AutoWB anymore! Especially with a modified 300D!

Cheers
Attached Thumbnails
Click for full-size image (300D_CloudyWB_OFF.jpg)
55.5 KB16 views
Click for full-size image (300D_CloudyWB_ON.jpg)
56.0 KB15 views

Last edited by Robby; 13-02-2006 at 12:15 PM.
Reply With Quote
  #11  
Old 13-02-2006, 11:28 AM
h0ughy's Avatar
h0ughy (David)
DOGHOUSE REBORN

h0ughy is offline
 
Join Date: Apr 2005
Location: NEWCASTLE NSW Australia
Posts: 30,680
looks close to me too Robby.
Reply With Quote
  #12  
Old 13-02-2006, 12:27 PM
Volans's Avatar
Volans
Registered User

Volans is offline
 
Join Date: Dec 2005
Location: Brisbane
Posts: 219
G'day All,

I can't vouch for the Canon 300D as I have a 350D (is there much of a difference?) but I was mucking around one Full Moon night and took the following shots. All settings are the same except for the White Balance.

5 second exposure, 1600 ISO and aperture set at 5.6

Image 1: WB = Tungsten
Image 2: WB = Fluro
Image 3: WB = Daylight
Image 4: WB = Cloudy
Image 5: WB = Flash
Image 6: WB = Auto

My camera has not been modified and I'll admit that it was
not done under normal astrophotographic conditions but the change in colour of the sky and the gum tree are quite obvious under different settings whereas other settings are almost identical.

Personally I like the WB set to Tungsten as it gives the sky a wonderfully rich blue.

Peter.
Attached Thumbnails
Click for full-size image (TN_IMG_3658.JPG)
9.5 KB19 views
Click for full-size image (TN_IMG_3659.JPG)
9.0 KB16 views
Click for full-size image (TN_IMG_3660.JPG)
8.5 KB11 views
Click for full-size image (TN_IMG_3663.JPG)
8.5 KB13 views
Click for full-size image (TN_IMG_3665.JPG)
8.4 KB16 views
Click for full-size image (TN_IMG_3666.JPG)
8.3 KB13 views
Reply With Quote
  #13  
Old 13-02-2006, 12:45 PM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
Thanks for that Peter. It would be interesting to compare these against a NoneWB setting. You didn't by chance shoot in RAW format?
I can see that the AWB is virtually identical to the Cloudy one... This is interesting... I wonder if the camera defaults to NoWB if it isn't obvious which one to use! This is where a RAW comparison would be invaluable.
Thanks for your input.
Cheers
Reply With Quote
  #14  
Old 13-02-2006, 01:04 PM
Volans's Avatar
Volans
Registered User

Volans is offline
 
Join Date: Dec 2005
Location: Brisbane
Posts: 219
Sorry Robby, I didn't take any RAW images but if it's clear tonight then I'll give it a crack.

Peter.
Reply With Quote
  #15  
Old 13-02-2006, 01:33 PM
Robby's Avatar
Robby
Registered User

Robby is offline
 
Join Date: Nov 2004
Location: Auckland, New Zealand
Posts: 1,079
Me too!!
Reply With Quote
Reply

Bookmarks

Thread Tools
Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT +10. The time is now 04:22 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2019, Jelsoft Enterprises Ltd.
Advertisement
SkyWatcher Australia
Advertisement
OzScopes Authorised Dealer
Advertisement
Meade Australia
Advertisement
Celestron Australia
Advertisement
Lunatico Astronomical
Advertisement
NexDome Observatories
Advertisement
Bintel
Advertisement
Astronomy and Electronics Centre
Advertisement