Jump to content

Banner.jpg.b83b14cd4142fe10848741bb2a14c66b.jpg

lines across image

gonzostar

Recommended Posts

gonzostar

gonzostar

Posted
Posted

Hi

Sunday night was fullish moon and some breaks in clouds. Attempted a few trial light frames of M51. Only 40mins of 300s frames. I am well aware i need more hours!

So thought would try my new camera. Canon 750d. I had a set of bias, and dark calibration frames ready, but no flats as yet for the new camera. Then i discovered parallel lines running across image.

40mins-m51.thumb.png.471ed81c2f23ef75ae2bf4ff5c7b8ede.png

I tried reprocessing without darks, bias to see if this was issue. But wasn't as lines still appeared in image

Is there a major issue or can a particular setting in DSS remove those parrallel lines?

Hope you can help

Thankyou 

Dean

Link to comment
Share on other sites
  • Replies 31
  • Created
  • Last Reply
tooth_dr

tooth_dr

Posted
Posted

I did a search for Canon 750d Horizontal Banding on google  

 

“ the 750d does have a banding issue due to the phase detection AF.  calibration (bias/darks/flats) does not help with this type of banding.”

 

 

Link to comment
Share on other sites
gonzostar

gonzostar

Posted
  • Author
Posted
8 minutes ago, tooth_dr said:

I did a search for Canon 750d Horizontal Banding on google  

 

“ the 750d does have a banding issue due to the phase detection AF.  calibration (bias/darks/flats) does not help with this type of banding.”

 

 

Have i just bought the wrong camera? Although i have seen a comment this could be due to heavy post processing?

Link to comment
Share on other sites
gonzostar

gonzostar

Posted
  • Author
Posted
7 minutes ago, steppenwolf said:

I can confirm that this is a known issue - the lines are caused by the Phase Detect Auto-Focus (PDAF) system.

Thanks for reply Steve. 

Is there away of turning this off? Would that make a difference, or should i exchange for another camera? Or maybe bands are exaggerated by heavy processing?

Cheers

Dean

Link to comment
Share on other sites
tooth_dr

tooth_dr

Posted
Posted
5 minutes ago, gonzostar said:

Nope :) I am not sure what happened there? I may have attached wrong format?

Cheers

Dean

Hi Dean. That’s a google sample image, not yours!. Do you lines look like that in you photo?

Link to comment
Share on other sites
tooth_dr

tooth_dr

Posted
Posted

I adjusted you image, I was on the phone earlier and couldn't see the lines that easily.  From what I've read, and from the above comments, the only way to remove the lines is through processing, it cannot be removed at source.

 

750_banding.jpg

Link to comment
Share on other sites
gonzostar

gonzostar

Posted
  • Author
Posted
1 minute ago, tooth_dr said:

I adjusted you image, I was on the phone earlier and couldn't see the lines that easily.  From what I've read, and from the above comments, the only way to remove the lines is through processing, it cannot be removed at source.

 

750_banding.jpg

Cool,  i processed image to heavily, therefore more hours of subs required. (and obviously flat frames :) )

Investigating in PS if there is bandind removal tool. somewhere!

Dean

 

Link to comment
Share on other sites
Stub Mandrel

Stub Mandrel

Posted
Posted
33 minutes ago, JohnSadlerAstro said:

Hi,

Dithering won't solve your problem, I'm afraid. What processing software are you using? Star Tools has a wonderful banding remover. :) 

John

I looked up the referenced quote about the banding being caused by the AF and it categorically states that dithering can cure it.

Link to comment
Share on other sites
gonzostar

gonzostar

Posted
  • Author
Posted
8 minutes ago, Stub Mandrel said:

I looked up the referenced quote about the banding being caused by the AF and it categorically states that dithering can cure it.

Thanks for taking your time looking this up. Will give it ago. Instead of dithering i4 will increase to 10 using backyard EOS. Will let you all know the results. At the moment looking at astronomy tools for PS. Wondering if there tools may help aswell :) 

Cheers Dean

19 minutes ago, tooth_dr said:

I adjusted you image, I was on the phone earlier and couldn't see the lines that easily.  From what I've read, and from the above comments, the only way to remove the lines is through processing, it cannot be removed at source.

 

750_banding.jpg

Cool,  i processed image to heavily, therefore more hours of subs required. (and obviously flat frames :) )

Investigating in PS if there is bandind removal tool. somewhere!

Dean

 

Link to comment
Share on other sites
tooth_dr

tooth_dr

Posted
Posted
11 minutes ago, gonzostar said:

Thanks for taking your time looking this up. Will give it ago. Instead of dithering i4 will increase to 10 using backyard EOS. Will let you all know the results. At the moment looking at astronomy tools for PS. Wondering if there tools may help aswell :) 

Cheers Dean

Cool,  i processed image to heavily, therefore more hours of subs required. (and obviously flat frames :) )

Investigating in PS if there is bandind removal tool. somewhere!

Dean

 

NC = Noel Carboni

He has a set of actions for PS

http://www.prodigitalsoftware.com/Astronomy_Tools_For_Full_Version.html

 

Link to comment
Share on other sites
steppenwolf

steppenwolf

Posted
Posted
2 hours ago, gonzostar said:

Is there away of turning this off? Would that make a difference, or should i exchange for another camera? Or maybe bands are exaggerated by heavy processing?

Unfortunately, it cannot be 'turned off' as it is part of the control architecture. I too tried Noel's banding action but it made zero difference. I would give dithering a try as it can be very good at removing line artefacts (like satellite trails) but I really don't know if it will help with this one or not - it has to be worth a go!

This sort of artefact will always be more apparent with heavy processing techniques but deep sky images by their very nature do require some serious work to release data unless you have a strong deep image.

Link to comment
Share on other sites
gonzostar

gonzostar

Posted
  • Author
Posted

Thanks Steve just downloaded NC astronomy tools and was going to give it a go tomorrow. Looks like if you cant do it then i have no chance. 

I use backyard EOS for dithering. its currently set at aggressiveness at 2. Will increase to say 10? for my setup? If this doesnt work then a trip back to camera shop ?

 

Dean

Link to comment
Share on other sites
ollypenrice

ollypenrice

Posted
Posted

I think Pixinsight has a Canon Banding Removel routine. I don't use a DSLR so I can't be more precise.

I'd have thought that dither would help but it would need to be on a scale large enough to move the target off the affected pixels on the chip - so a pretty large dither. How wide are the bands? If each dithered image puts the same strip of sky under the band it won't work.

To be honest the cooled CMOS cameras are so much closer to DSLR prices than was the case with CCD that avoiding these hassles at source seems to me to be more desirable than ever.

Olly

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. By using this site, you agree to our Terms of Use.