Author Topic: I need a very detailed tutorial on processing raw pics Taken with my T3i  (Read 876 times)

Offline rtemen

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Greetings.  (this is kind of long  :) )
I have been working with Pixinsight for a goodly while now, and I am 'stuck' on a couple of issues.
For about a half a year now, I have been following the image processing video by Richard Bloch.
After some practicing, I have been getting better at processing.
However, I seemed to be at a point where I couldn't get things any better.
After several discussions on this forum, one member told me that when using a camera like my T3i, I needed to process all of my flats, darks,bias, etc, using the Raw and CFA settings in the Format Hints, and only when I get to the point that the Lights have been calibrated, do I use the DeBayer tool to convert the pics to color.
After following the examples that he pointed me to, my results are much worse than my Richard Bloch results.

So, here are the big questions:
Is it true that all of my processing should be done in the RAW CFA formats?
If so, is there a tutorial that will walk me through a thorough workflow on processing my files in this mode?

Rich

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if you are referring to me, well, ok.

"all of your processing" should not be done in the RAW CFA format. all of your preprocessing should. after you have debayered your lights, they are no longer RAW CFA, but RGB. you align and stack the RGB images. then you process your master light.

you might want to take a look at some different tutorials...

http://www.lightvortexastronomy.com/tutorial-example-m31-andromeda-galaxy---dslr.html

in particular read the articles linked to in the "assumed" section which describes the preprocessing flow. you'll find that what i suggested is not really any kind of exotic or wrong advice, it is just how it has to be done.

rob

Offline rtemen

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Hi, Rob.
I truly do not recall who told me this before.  There were so many people helping, I don't know who told me what at this point.
I have not been working on my astronomy for several months now due to the high heat here in Phoenix.  So, I am starting anew.
That being said, I am not implying what you told me is wrong, just that I might need a more detailed tutorial.
For example, if I lets say, follow the steps to make my master dark using the steps showing Raw and CFA, is there any way to check the result to see if it worked properly.
So, I will go to the link you suggested and see what I can learn or do in more detail to be sure I have it right.

Thanks,
Rich

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well let me ask: before, were you letting some other program convert the CR2 to tiff? because what happens when you do that is that the image gets stretched and a saturation boost - the images have been preprocessed, and so they look a little better. when you do the full calibration flow using raw cya, you're left with linear data that needs stretching, curves, saturation boost, etc. after debayering/alignment/stacking.

it's hard to know if the master darks, etc. are "correct" without really doing a lot of analysis. in the end though if you calibrate and debayer an image and then apply an autoSTF with the channels unlocked, it should look "reasonable" as long as the sub exposure length was long enough (meaning, there's enough data in the sub to really see anything.)

rob

Offline rtemen

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No, I didn't let anything change them to tiff's. 

However, I do want to thank you for the link to that tutorial.
It was a longer process then I have gone through before, but, FINALLY, I see a great improvement in my results now.
This tutorial was more detailed and had more steps to go thru, but it helped a lot.

Thanks, again.
Rich

Offline John_Gill

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Hi,

I have created a summary text file of the tutorial supplied by www.lightvortxastronomy.com  I use this to guide me thru the entire pre- and post- processing routine.  If you want a copy, then send me your email address.

Look up
John
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