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Canon 750D Phase Detect Auto-Focus (PDAF) pixels on the sensor banding  

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(@maciekja)
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Joined: 3 years ago
Posts: 12
April 12, 2021 21:41  

Is it possible in terms of software to get rid of horizontal banding lines?

The problem is, the Canon matrix has lines of Phase Detect Auto-Focus (PDAF) pixels on the sensor. Unfortunately, this is caused by horizontal lines all over the frame. They are perfectly visible on the calibration frames as well as in a highly stretched photo.

Using dithering does not remove this. Although I haven't tried to do dither by e.g. 20 px yet.

I include a stretched stack, a stretched MasterBias and a Master Dak Flat.

integration1
masterbias1
masterdarkflat

 

Here is more information: http://photomacrography.net/forum/viewtopic.php?t=30169

This topic was modified 1 month ago by maciekja

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(@vincent-mod)
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April 13, 2021 11:13  

Interesting, I didn't know about that, thanks for sharing! Is this not corrected by the dark as I understand you're saying?


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(@maciekja)
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April 13, 2021 11:18  

@vincent-mod

I'll put in a screen from stretch DarkFrame later.
But I think that if this pattern is always in the same place on every frame (light, flat, bias, dark) it can be quite a problem (for me).


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(@vincent-mod)
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April 13, 2021 11:21  

Mmm, well that will depend on if it gets removed by the calibration data. If it's also in the bias, the flat will be corrected for instance, the darks might take care of the lights (not 100% sure). The proof will be in the pudding. 😉


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(@maciekja)
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April 13, 2021 18:50  

@vincent-mod

This is MasterDark. Unfortunatelly it's not removing this baning.

MasterDark

 


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(@vincent-mod)
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April 14, 2021 09:50  

Mmm, but I'm not seeing the banding in that masterdark right?

I'm afraid I don't have more information on this specific issue, if the bias doesn't get it out it might be an issue that's more difficult to solve.


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(@maciekja)
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April 14, 2021 09:54  

@vincent-mod

I was afraid of this that it would not be that simple.


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(@vincent-mod)
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April 14, 2021 09:55  

But what about your masterdark, I don't see the banding in there so maybe it does work?


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(@maciekja)
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April 14, 2021 10:00  

@vincent-mod

That's right, you can't see this banding on MasterDark. But he is on the stack. Of course after the stretch.

I can put downloads (light, flat, bias, dark) if you want to check it out for yourself. Maybe you can do better than me 🙂


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(@vincent-mod)
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April 14, 2021 10:08  

Yes, that's a good idea. 🙂 I'm just wondering, I'll have a play with it, just upload 20 bias, 20 darks, 20 flats and 20 lights. That should be enough.

Go to https://upload.astropixelprocessor.com and use upload1 as username and upload1 as password.

Create a directory named “maciekja-bandingIssue” and upload in there. Thank you!


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(@maciekja)
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April 14, 2021 10:22  

@vincent-mod

Ok, I'll do it when I'm in front of my home computer.


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(@karolbe)
Molecular Cloud Customer
Joined: 1 year ago
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April 14, 2021 16:48  

The only working (not fully but let say in 80%) solution for me was to use.....PixInsight and the Canon Banding Removal tool. ISO 1600 also helped a bit in compare to ISO 800. But generally speaking 750D is not the greatest choice for AP. I am going to sell mine and buy 6D.


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(@maciekja)
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April 14, 2021 19:45  

@karolbe

As you say Pix deals with it in some way, but not 100% either. I was doing my frames on ISO1600 because on ISO800 it was noticeably worse.


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(@maciekja)
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April 14, 2021 22:09  

@vincent-mod

I've upload all data. It's in folder Canon 750 Banding.


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(@vincent-mod)
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April 17, 2021 20:39  

Thanks, downloading it today and will have a look.


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(@minusman)
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Joined: 4 years ago
Posts: 193
April 18, 2021 19:34  

There is a way to get rid of banding.
The program Siril has a tool for this, the Canon Banding Script.
You can also use it for color images from OSC CMOS cameras.
Siril can be downloaded for free. The script is also used in Pixinsight.
Unfortunately, such a function is missing in APP.

Canon750D Bandig H remove
2021 04 18 19 20 Horizontal Banding Remove

 

2021 04 18 19 20 Vertical Banding
2021 04 18 19 24Vertical Banding removed

With best regards.


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(@vincent-mod)
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April 18, 2021 19:43  

Yes, I think Minusman is right, I wasn't able to completely get rid of it. So that may be something for Mabula to  consider if it isn't already on his list, I'll pass it on.


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(@maciekja)
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April 19, 2021 10:49  

And I already started considering the Canon 6D;) Maybe I can work with what I have.

Thanks for the answer!


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