Go Back   IceInSpace > Equipment > Astrophotography and Imaging Equipment and Discussions
Register FAQ Calendar Today's Posts Search

Reply
 
Thread Tools Rate Thread
  #1  
Old 13-03-2008, 11:59 PM
Stargazer292's Avatar
Stargazer292
Eppur si muove!! Galileus

Stargazer292 is offline
 
Join Date: May 2007
Location: Perth - WA
Posts: 39
RAW files

Hi everybody,
Can someone please explain the advantage of using RAw images and how to use them for astroimaging. Thankz
Reply With Quote
  #2  
Old 14-03-2008, 06:12 AM
madwayne's Avatar
madwayne (Wayne)
Registered User

madwayne is offline
 
Join Date: Jun 2007
Location: Robertson NSW
Posts: 517
Hi Andrew,

I think you will find what you are looking for, and more, in this post.

http://www.iceinspace.com.au/forum/s...ad.php?t=29699

It's an interesting read, in my opinion, and very well written.

Clear skies.
Reply With Quote
  #3  
Old 14-03-2008, 08:36 AM
bojan's Avatar
bojan
amateur

bojan is offline
 
Join Date: Jul 2006
Location: Mt Waverley, VIC
Posts: 7,027
Quote:
Originally Posted by madwayne View Post
Hi Andrew,

I think you will find what you are looking for, and more, in this post.

http://www.iceinspace.com.au/forum/s...ad.php?t=29699

It's an interesting read, in my opinion, and very well written.

Clear skies.
This is a very good paper, indeed.
However, for a beginner, it might be a bit too much of technical details...
So, in a nutshell, RAW format is better simply because it contains ALL the data collected by camera during exposure.
JPG (or some other formats) file does not because:
- the resolution depth is 8-bits per colour channel (original data could be up to 14 bits per ch, 400D has 12 bits.. still MUCH better than 8)
- lots of information is also lost due to the compression (compression algorithm is substituting real information with similar standard patterns, reducing the size of the file this way by storing just a list of those patterns and not the patterns themselves). Obviously, the jpg image will look similar to the original, but if you have a closer look by zooming into high contrast details, you would be able to see the artifacts of compression, which may be very visible if compression is high. So you will actually see what was not really there...
- Subsequent saving of the jpg image (after some editing for example) will deteriorate the quality of the image to the point of destroying it. RAW file remains intact in that respect (except for the changes done, of course).
Reply With Quote
  #4  
Old 14-03-2008, 06:52 PM
leon's Avatar
leon
Registered User

leon is offline
 
Join Date: Apr 2006
Location: Warrnambool
Posts: 12,658
Yep, what you have just said has nailed it pretty well, raw capture is the way to go, and from there on you can work with the data collected.

Leon
Reply With Quote
Reply

Bookmarks


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 03:50 AM.

Powered by vBulletin Version 3.8.7 | Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Advertisement
Bintel
Advertisement