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Esteemed Contributor
Posts: 4,897
Registered: ‎06-25-2014

Re: Rebel T6I Sky Banding?


@Peter wrote:

I see 14 lines (7 pairs) in the first one and with exactly same distance to each other. I would say that is is time to send the camera to Canon for a repair if Canon is able to fix it with interpolation or mapping out the lines. It is a known issue with Canon M3, 750D and 760D. If you unmount the lens and take a look at the sensor, you will see 7 lines.

 

If you check the lines, you will see that you will not have 6 pairs or 8 pairs. You will always get 7 pairs.This is caused due to the Hybrid CMOS AF III system. You can search at google pictures with the keywords Hybrid_CMOS_AF_Generations

 

I think that if you use Canon Digital Photo Professional 4 the software will mask the problem a little bit.


The 70D and the 80D have the hybrid CMOS system too, don't they? Does it happen to them too?

Bob
Philadelphia, Pennsylvania USA
Super Contributor
Posts: 140
Registered: ‎12-03-2016

Re: Rebel T6I Sky Banding?

[ Edited ]

This has been discussed many times on astrophotography forums.  There, it is an issue that occurs when frames are stacked during post processing ... especially deep sky photos.  Some users reported similar issues with Sony sensors on other cameras, and it is assumed to be an interpolation problem in the AF portion of the sensors.

 

I have been unable to replicate the problem with my own T6S, and I have tried.  The problem the OP reports here may be more than the known AF sensor issue, since it doesn't seem to be related to frame stacking or other extreme processing techniques.  This could be a straightforward sensor defect, rather than the design shortcoming associated with the typical banding problem.

Reputable Contributor
Posts: 730
Registered: ‎11-14-2012

Re: Rebel T6I Sky Banding?

[ Edited ]

@RobertTheFat wrote:

@Peter wrote:

I see 14 lines (7 pairs) in the first one and with exactly same distance to each other. I would say that is is time to send the camera to Canon for a repair if Canon is able to fix it with interpolation or mapping out the lines. It is a known issue with Canon M3, 750D and 760D. If you unmount the lens and take a look at the sensor, you will see 7 lines.

 

If you check the lines, you will see that you will not have 6 pairs or 8 pairs. You will always get 7 pairs.This is caused due to the Hybrid CMOS AF III system. You can search at google pictures with the keywords Hybrid_CMOS_AF_Generations

 

I think that if you use Canon Digital Photo Professional 4 the software will mask the problem a little bit.


The 70D and the 80D have the hybrid CMOS system too, don't they? Does it happen to them too?


70D uses Dual Pixel CMOS AF if I am not wrong.100D, 650D, 700D (Hybrid CMOS AF II?) on the other side have similar problem when video recording in raw format with Magic Lantern.


@StanNH wrote:

This has been discussed many times on astrophotography forums.  There, it is an issue that occurs when frames are stacked during post processing ... especially deep sky photos.  Some users reported similar issues with Sony sensors on other cameras, and it is assumed to be an interpolation problem in the AF portion of the sensors.

 

I have been unable to replicate the problem with my own T6S, and I have tried.  The problem the OP reports here may be more than the known AF sensor issue, since it doesn't seem to be related to frame stacking or other extreme processing techniques.  This could be a straightforward sensor defect, rather than the design shortcoming associated with the typical banding problem.


As I wrote I didn´t see any lines when I tonemapped heavily with other´s raw files than OP´s.
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Reputable Contributor
Posts: 730
Registered: ‎11-14-2012

Re: Rebel T6I Sky Banding?

[ Edited ]

@ElectricMuppet wrote:

Alright, I'll be about 10-20 minutes. I need to let my battery charge a bit. I'll post the processed photos here and send you the raw's via email again.

What I was shooting from was a Rokinon 14mm 2.8 UMC lens without an AE chip.


Took a look at your raw files you sent me. The first ones had visible banding. The last ones were to bright I think. Anyway, Canon lens or not doesn't matter. Call on Monday and tell them that you are able to see 7 pairs of banding from the Hybrid CMOS AF III with your T6i. This occur in normal photo condition without tonemapping. You should also send Canon the picture of the power line with the blue sky. Don't forget to update us.

---------------------------------------------------------
My Swedish blog

M5, 7D, 6D, D30, 300D, 30D, 1000D IR, EOS DCS 3c, EOS D2000, 16-35/4L IS, 100/2,8 Macro, 70-200/2,8L IS II, 24-105/4L, 85/1,8, 50/1,4, 24/1,4L II, 300/2,8L IS, Helios 58/2

Darktable, RawTherapee, Photomatix, Luminance HDR, GIMP 2.10.6.
VIP
Posts: 10,937
Registered: ‎12-07-2012

Re: Rebel T6I Sky Banding?

Respectively, you guys can mess with this issue all you want but in the end you will find it is a bad SD card or a bad sensor.  The SD card is easy.  OP doesn't want to try a new one. The bad sensor is a trip to Canon service. Call Canon and ship!

 

IMHO, as always. of course.

EOS 1DX and 1D Mk IV, even less and less other stuff.
Frequent Contributor
Posts: 27
Registered: ‎02-10-2017

Re: Rebel T6I Sky Banding?


Took a look at your raw files you sent me. The first ones had visible banding. The last ones were to bright I think. Anyway, Canon lens or not doesn't matter. Call on Monday and tell them that you are able to see 7 pairs of banding from the Hybrid CMOS AF III with your T6i. This occur in normal photo condition without tonemapping. You should also send Canon the picture of the power line with the blue sky. Don't forget to update us.


 Thank you for everything! I surely will update once I get my camera back. I will most likely ship tomorrow after I talk to Canon support.

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Frequent Contributor
Posts: 27
Registered: ‎02-10-2017

Re: Rebel T6I Sky Banding?


@ebiggs1 wrote:

Respectively, you guys can mess with this issue all you want but in the end you will find it is a bad SD card or a bad sensor.  The SD card is easy.  OP doesn't want to try a new one. The bad sensor is a trip to Canon service. Call Canon and ship!

 

IMHO, as always. of course.


Thank you ebiggs1 for the reply and advice.

I just took the SD cards from two of my Nintendo 3DS's to test what you're saying. out of the three SD cards I used all of them are still showing said problem. I highly doubt all three of my cards are garbage. I'm positive I can write it off as it's not my SD card. I think from what others have been saying that it is infact a bad sensor. 

This is a photo thats been slightly retouched from one of the 3DS cards I used. You can see them in the original untouch photo but I didn't want people to have their faces against their monitors squinting their eyes trying to find silly lines on a image. It was also snowing again today so those black lines are infact snow again and not gunk on the sensor.

banding4.jpg

VIP
Posts: 10,937
Registered: ‎12-07-2012

Re: Rebel T6I Sky Banding?

"I highly doubt all three of my cards are garbage."

 

I do too, now.  You must admit that  was an easy test to see if the only other probability.  Besides Canon will probably ask you if you tried different SD cards!  It is a bad sensor.

EOS 1DX and 1D Mk IV, even less and less other stuff.
Frequent Contributor
Posts: 27
Registered: ‎02-10-2017

Re: Rebel T6I Sky Banding?

Hello everyone! I ended up shipping my Rebel a few days ago and just got the notification in my email today that Canons shipping it back to me today. Hopefully they fixed my issue. I'm kinda weary though since it only took them four days to repair it when they recieved it. They gave me a window of 7-10 days.. is this normal?



Esteemed Contributor
Posts: 3,234
Registered: ‎02-17-2016

Re: Rebel T6I Sky Banding?

Yes, Canon is really good about meeting deadlines.

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