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What is wrong with my Sony A7IV?

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15 replies to this topic

#1 Aman Dude

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Posted 21 April 2024 - 10:21 PM

I made sure this thing was clean of smudges and dust spots. For some reason after DBE in PixInsight, It looks like this. What the heck could be wrong?

 

Screenshot 2024-04-21 232038.png



#2 rj144

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Posted 21 April 2024 - 10:33 PM

Did you take flats?


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#3 Aman Dude

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Posted 21 April 2024 - 10:33 PM

Did you take flats?

No, I did not yet. This is some test data.



#4 rj144

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Posted 21 April 2024 - 10:35 PM

No, I did not yet. This is some test data.

Well, flats will fix that, so don't worry.


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#5 Aman Dude

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Posted 21 April 2024 - 10:37 PM

Well, flats will fix that, so don't worry.

Will they fix the wavy vertical banding too? Or just the dust spots?



#6 rj144

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Posted 21 April 2024 - 11:11 PM

Will they fix the wavy vertical banding too? Or just the dust spots?

Did you take any calibration pics?  Is this one sub or a stacked sub?  If it's stacked what are the details?   Also, what are the details on a sub?



#7 sharkmelley

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Posted 21 April 2024 - 11:13 PM

Will they fix the wavy vertical banding too? Or just the dust spots?

Flats will fix the dust spots but they may not fix the wavy vertical banding.  It depends on the cause of the wavy banding.  For instance, my Sony A7S had green/purple vertical swathes that I was never able to calibrate.  Believe me, I tried everything.



#8 Chrisofweden

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Posted 22 April 2024 - 12:23 AM

In the past I imaged using an A7IIIR and even after correct calibration I would sometimes be left with this “striping” in my stacked image.
When the problem arose, I used a script in PI called “Canon Color banding” (or something like that).
It usually helped :)
Give it a try, it can’t hurt :)

/Chris
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#9 Aman Dude

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Posted 22 April 2024 - 08:01 AM

Well, flats will fix that, so don't worry.

After Flats it still has issues:

Screenshot 2024-04-22 090051.png



#10 rj144

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Posted 22 April 2024 - 08:07 AM

After Flats it still has issues:

attachicon.gif Screenshot 2024-04-22 090051.png

But they weren't taken or applied correctly or else you wouldn't see the dust motes.  Did you take bias?  

 

Again, is this a stack or a sub?  What's the details?



#11 Aman Dude

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Posted 22 April 2024 - 08:11 AM

But they weren't taken or applied correctly or else you wouldn't see the dust motes. Did you take bias?

Again, is this a stack or a sub? What's the details?


This was 600 30sec subs and I took the flats outside using a clear sunny sky and used 1/160 shutter for that, same for the dark flats and all at ISO 400. Stacked in Deep Sky stacker
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#12 rj144

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Posted 22 April 2024 - 08:17 AM

This was 600 30sec subs and I took the flats outside using a clear sunny sky and used 1/160 shutter for that, same for the dark flats and all at ISO 400. Stacked in Deep Sky stacker

You mean in the middle of the day?  I never do sky flats, but I think everyone takes them at dusk or in the morning.  Is the striping in a single sub?



#13 bbasiaga

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Posted 22 April 2024 - 08:26 AM

This was 600 30sec subs and I took the flats outside using a clear sunny sky and used 1/160 shutter for that, same for the dark flats and all at ISO 400. Stacked in Deep Sky stacker


You need to be focused at infinity, and put something like a t shirt over the lens. Mid day in the sun 1/160 sounds way too long for a flat. The histogram should ideally be in the center, or just left if it.

Brian
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#14 rj144

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Posted 22 April 2024 - 08:59 AM

You need to be focused at infinity, and put something like a t shirt over the lens. Mid day in the sun 1/160 sounds way too long for a flat. The histogram should ideally be in the center, or just left if it.

Brian

The focus should be close to infinity, but it should be exactly the same focus as the lights.


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#15 Aman Dude

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Posted 22 April 2024 - 08:04 PM

You need to be focused at infinity, and put something like a t shirt over the lens. Mid day in the sun 1/160 sounds way too long for a flat. The histogram should ideally be in the center, or just left if it.

Brian

I did but still get the same kinda thing.



#16 DanMiller

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Posted 22 April 2024 - 08:31 PM

If the canon banding script doesn't clean them up, as another reply indicated. Sirill also has a script that is very good at correcting that type of banding.  Sirill is free.  Also, the GradiantCorrection process in Pixinsight cleans up a lot of my banding.  I image with an old Canon, so I have to clean up banding all the time. 

 

So, do your calibration frames.  Process in WBPP with everything, see if the banding is still bad.  And run the gradiantcorrection process.  If still have banding, run the canon banding script in pixinsight.  If still something left, then download Sirill and run it's banding script.  You will be surprised at the results.

 

Dan


Edited by DanMiller, 22 April 2024 - 08:35 PM.



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