Canon banding becoming over powering.

[Nigel G]

I have noticed my banding problem getting worse.

Its causing problems, there's good software to tackle it but now its getting worse its still visible after all the tricks I have learnt.

I have been using N/B filters and longer exposures for a couple of months.

My last session is the worst and only 600s exposures when I have been using upto 30 minute exposures with less banding.

Question.. Should the banding get worse over time and use, I'm guessing its to do with the sensor.

My Camera is a self modified 1200D, If I get the colour bayer array removed would this help ?

Or am I in desperate need of a new camera.

A sample below, 21 x 600s ISO800 12nm Ha clip filter, dithered. Gradient wiped and stretched to show the banding, and a worked on image. Detail is getting lost in trying to reduce the bands.

Any advise is greatly appreciated.

I have tried StarTools banding, PS add on's, PI trial and canon digital photo pro. Each has its improvements but non can completely resolve the problem yet.

 

Cheers

Nige.

 

Edited December 31, 2017 by Nigel G

[tooth_dr]

Daft question probably but could there be a power cable near the USB cable, or are you using a usb hub? I only ask because I got banding with my Canon when I ran the usb cable beside (in same duct as) the 12v power cable.

Ive used four Canons avd never seen this except when above issue arose. Is it specific to 1200d?

[Starflyer]

I've seen this in the past in various canon cameras, IMO it's temperature related, try checking the internal camera temp in the EXIF data for subs where it's better and where it's worse.

The more you stretch the data the more the banding shows, so for the shorter exposures it may look worse because you're having to stretch it harder.

I ended up cooling my 450D and at EXIF temps below 9 or 10C the banding completely disappeared.

Cheers

Ian

 

[Nigel G]

 

25 minutes ago, tooth_dr said:

Daft question probably but could there be a power cable near the USB cable, or are you using a usb hub? I only ask because I got banding with my Canon when I ran the usb cable beside (in same duct as) the 12v power cable.

Ive used four Canons avd never seen this except when above issue arose. Is it specific to 1200d?

Thanks for your reply and very interesting.

I run my cables loose to the equipment from my conservatory, they all run out the door together, camera USB, guide cam USB and mains to 12v converter which sits next to the 2 USB cables.

Now the interesting thing is and I hadn't thought about it, the banding probably got worse after I started using mains power instead of my 12 power pack a few months ago.

This last image was a new way, we have a new 18 y old cat so can't keep the doors open yet so I ran the cables out of a window together.

You might have hit the nail on the head  

Thanks  can't wait for the next clear spell, I will try by separating the power cable completely.

I will let you know the results  

Nige.  

[Nigel G]

2 minutes ago, Starflyer said:

I've seen this in the past in various canon cameras, IMO it's temperature related, try checking the internal camera temp in the EXIF data for subs where it's better and where it's worse.

The more you stretch the data the more the banding shows, so for the shorter exposures it may look worse because you're having to stretch it harder.

I ended up cooling my 450D and at EXIF temps below 9 or 10C the banding completely disappeared.

Cheers

Ian

 

Thanks Ian.

The last session outside temp was well below 0. The banding has been better in summer conditions 20 degree heat.

But a very valid point, I have never known how to check the sensor temp, I use Canon EOS utility to capture and never found a temp reading on that or the camera, excuse my ignorance but I'm not sure what EXIF data is  

Cheers

Nige.

[ronin]

As it reads it is not debayered then the sensor+mask will be a row or RGRGRGRGRGRGRG, then a row of BGBGBGBGBGBGBG.

With a Ha filter in then a row of BGBGBG gets in effect no illumination on it and would remain a dark band, even the RGRGRGRG gets just alternative pixels illuminated. Since it is still fundimentally a general purpose camera for holidays, landscapes, nature and sports shots it makes me wonder how the software of the camera gets around all this.

One sort of option is that the internal software is just trying to boost the level to get the G and B row of pixels up but it will do some to the R so possibly making the banding worse. What is the result without any NB filters, just simple OSC use ?

I do wonder if getting a DSLR, modifing it, swapping filters and then debayering it and still it is uncooled and remains a DSLR with whatever limitations is really more economic then just buying a ZWO or Atik that is built for the purpose.

[MarkyD]

41 minutes ago, Nigel G said:

Thanks Ian.

The last session outside temp was well below 0. The banding has been better in summer conditions 20 degree heat.

But a very valid point, I have never known how to check the sensor temp, I use Canon EOS utility to capture and never found a temp reading on that or the camera, excuse my ignorance but I'm not sure what EXIF data is  

Cheers

Nige.

EXIF data contains all of the image information recorded by the camera (date, time, GPS loctaion, shutter speed etc) If you download the free program IrfanView you can view the EXIF data from this.  It is also a very handy program for batch processing etc

[Nigel G]

6 minutes ago, ronin said:

 

One sort of option is that the internal software is just trying to boost the level to get the G and B row of pixels up but it will do some to the R so possibly making the banding worse. What is the result without any NB filters, just simple OSC use ?

 

The banding has been a problem since I could take longer than 2 minute sub's. before I modified it and without filters makes no difference. The longer the exposure the more banding it seems.

I'm kinda thinking the electrical interference could be the main issue as it all adds up.

Only one way to find out.  

Cheers.

Nige.

[Nigel G]

1 hour ago, tooth_dr said:

 

Ive used four Canons avd never seen this except when above issue arose. Is it specific to 1200d?

I get banding but not so obvious with my unmodified 1300D. 

[michaelmorris]

My understanding is that banding is likely to get worse the more you stretch an image.  If your tracking and /or guiding is spot on, stacking subs will just increase the problem.  One way around this is to dither between each sub.  

Dithering is moving the mount by a small random distance between each sub-exposure (just a few pixels).  Therefore whilst the fixed pattern noise stays in the same place on each sub-exposure, the stars are in slightly different places on each image. When you come to stack these sub-exposures the stacking software aligns each image on the stars.  When these are stacked the stars are nice and sharp, but the fixed pattern noise tends to get smeared as it is offset between each aligned image.  The nett result is that all forms of fixed pattern noise (including dark or hot pixels) tend to disappear more into the background, allowing you to stretch the final image more.

http://dslr-astrophotography.com/dithering-optimal-results-dslr-astrophotography/

APT image capture software has some great dithering tools including integration with PHD guiding software and dithering when not autoguiding.

https://ideiki.com/astro/Default.aspx

I hope this helps

 

[Nigel G]

5 minutes ago, michaelmorris said:

My understanding is that banding is likely to get worse the more you stretch an image.  If your tracking and /or guiding is spot on, stacking subs will just increase the problem.  One way around this is to dither between each sub.  

Dithering is moving the mount by a small random distance between each sub-exposure (just a few pixels).  Therefore whilst the fixed pattern noise stays in the same place on each sub-exposure, the stars are in slightly different places on each image. When you come to stack these sub-exposures the stacking software aligns each image on the stars.  When these are stacked the stars are nice and sharp, but the fixed pattern noise tends to get smeared as it is offset between each aligned image.  The nett result is that all forms of fixed pattern noise (including dark or hot pixels) tend to disappear more into the background, allowing you to stretch the final image more.

http://dslr-astrophotography.com/dithering-optimal-results-dslr-astrophotography/

APT image capture software has some great dithering tools including integration with PHD guiding software and dithering when not autoguiding.

https://ideiki.com/astro/Default.aspx

I hope this helps

 

Thanks Michael.

I do dither between each sub at least 10 pixels and very random, a lot vertically, which helps and almost did rid the problem certainly reduced the banding until this one and a few before, as I'm now exposing for 15 -30 minutes with N/B filters its becoming very obvious but got extreme after running all the cables through the window.

When I last imaged Andromeda I had to do a meridian flip which helped loads as well as dithering.

I'm not sure if you can dither to much ?

Cheers

Nige.

[michaelmorris]

I would have thought that 15-30 minute exposures is going to be really pushing the limits of DSLR astrophotography and as a result I'm not surprised that you're getting banding.  I know it is not ideal, but would have thought that taking more, shorter, exposures might help.

[Nigel G]

11 minutes ago, michaelmorris said:

I would have thought that 15-30 minute exposures is going to be really pushing the limits of DSLR astrophotography and as a result I'm not surprised that you're getting banding.  I know it is not ideal, but would have thought that taking more, shorter, exposures might help.

Very good point  

I do tend to try and find the limits of my equipment.

Also getting fewer subs to stack with longer exposures which wouldn't help.

[michaelmorris]

20 minutes ago, Nigel G said:

I do tend to try and find the limits of my equipment.

Well I suspect you may have just found them! 

Edited December 31, 2017 by michaelmorris

[tooth_dr]

9 minutes ago, michaelmorris said:

Well I suspect you may have just found them! 

I still think it’s electrical interference 

and not operator related 

[Nigel G]

I'm thinking mainly electrical interference but also getting close to what my 1200D is capable of.

A combination of things. 

We shall hopefully find out next clear night.

I could do a long exposure test in the shed tonight. no power cable nearby.

[michael8554]

Take some Images with a camera battery installed.

Michael 

[Nigel G]

6 hours ago, michael8554 said:

Take some Images with a camera battery installed.

Michael 

Hi Michael,  I  only ever use batteries in my camera, it's the mount power cable potentially causing the problem.  ☺

Cheers 

Nige 

[tooth_dr]

Hopefully it’ll be clear with you tonight!

[Nigel G]

1 hour ago, tooth_dr said:

Hopefully it’ll be clear with you tonight!

Forecast partly clear, so its possible  

[davew]

Just a thought here Nigel but why are you waiting to waste a clear night ? Can't these experiments be done any old night ?

In fact, I would have thought you could just cap the scope and do it practically any time so long as the temperature isn't too high.

Good luck with it,

Dave.

[Nigel G]

19 minutes ago, davew said:

Just a thought here Nigel but why are you waiting to waste a clear night ? Can't these experiments be done any old night ?

In fact, I would have thought you could just cap the scope and do it practically any time so long as the temperature isn't too high.

Good luck with it,

Dave.

Very true, I'm on to it now, a couple of tests, 

1 save straight to card,  not connected to the PC maybe camera in the fridge for this one.

2 save to PC via USB no power cable nearby. 

Cheers 

Nige 

[davew]

I would try every scenario you can think of.

One thing I would definitely try is to actually make it happen. Then find ways to prevent it. That way you'll be fully armed for the future.

Dave.

[ollypenrice]

The arrival of monochrome CMOS cameras similar in format to DSLRs and at considerably sub-CCD prices inclines me to remind you of a phrase in your original post: Or am I in desperate need of a new camera?

I hesitate to answer this too assertively but if I were to do so the answer would begin with a 'y'.

lly

Edited January 1, 2018 by ollypenrice
Typo

[carastro]

I am inclined to agree with Olly, but in the meantime, here is a tip I was given some years ago:

Do you keep your SD card in the camera when you download to the laptop? 

I was told that removal of the SD card reduces this problem because something electronic (which I don't understand) can happen in the download due to the SD card being in place.  Anyway, I removed my SD card and it greatly improved/got rid of the horizontal banding problem.  This was some years ago, so I can't remember all the details 100%.

Might be worth a try though, and as stated previously try not to let power cables touch USB cables.

Carole