Author Topic: Banding when using Dual-ISO  (Read 1265 times)

bdavid32

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Banding when using Dual-ISO
« on: July 27, 2016, 11:25:51 AM »
Hi,
First of all, I would like to say a big thank you to everyone who contributed to the development of ML – it really is an exceptional tool!

I leave Dual ISO enabled most of the time on my 5D II, with the +2EV Recovery ISO option. Most of the images have vertical and horizontal banding — more or less pronounced, depending on circumstances I haven't been able to identify yet.

The files I have uploaded prove that the amount of banding can vary a lot between two images of approximatively the same scene, taken at the exact same settings, processed in the same way.

This is an example of what it looks like at worst :


Please note the image is not pushed more than +1EV in post. Sharpness and NR are at default LR settings. The data in the squares is still in the midtone overlapping area.

The "problematic" photo (IMG_2241) can be downloaded from here: https://www.amazon.com/clouddrive/share/Lgdteww54UwrLw9nu2dSTIEssKthsQEf7KPOftGkHvH?ref_=cd_ph_share_link_copy
The other two photos in the link (IMG_2240 and IMG 2242) are taken before, respectively after the problematic one – and they seem to be much less affected by banding – but still, some horizontal banding is noticeable, especially in lower area of the sky.

The DNG conversion was done using the Dual ISO Converter LR plug-in, 3.0-BETA3 for Mac. I have tried all the possible setting combinations, nothing seems to make it better (except no-fullres, for obvious reasons).

I tend to think there is a problem with the converter, but I might be wrong. If any of you can download the files and convert them, I'd be really grateful :)

Thanks in advance for any input!

bodhidharmazen

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Re: Banding when using Dual-ISO
« Reply #1 on: November 08, 2018, 10:10:17 PM »
I'm having this exact problem. Apparently no one else is experiencing this? Is there a setting for avoiding it?

I'm using a 5Dmk2 with barracuda gui and latest cr2hdr I found on ML web.

I use default parameters.

PLEASE HELP

dfort

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Re: Banding when using Dual-ISO
« Reply #2 on: November 09, 2018, 12:22:01 AM »
Looks to me that the problem is the shot is very underexposed. I usually open the shadows and recover the highlights in LR to see how much dynamic range I can pull out of it before messing around with the exposure. As you can see, this shot is very dark. Lightening this up will certainly bring up a lot of noise.



Note that this isn't "banding," this is noise. The noise in Dual ISO images look different from "normal" images because it is blending the alternating high and low ISO lines that make up the image.
5D3.* 7D.206 700D.115 EOSM.203 EOSM2.103 M50.102

bodhidharmazen

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Re: Banding when using Dual-ISO
« Reply #3 on: November 09, 2018, 11:47:20 AM »
Thanks dfordt,

Banding might be the wrong word, the lines (I presume) are the result of the blending between the low and high iso interleaving. That said, I believe there most be a way that, in post processing, those lines can be diffused or blended in a software way.

I get those lines in many images, sometimes just in the clouds where its more evident than say on a textured surface, but they are very distracting.

Sapporo

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Re: Banding when using Dual-ISO
« Reply #4 on: November 09, 2018, 08:22:10 PM »
Hi,
First of all, I would like to say a big thank you to everyone who contributed to the development of ML – it really is an exceptional tool!

I leave Dual ISO enabled most of the time on my 5D II, with the +2EV Recovery ISO option. Most of the images have vertical and horizontal banding — more or less pronounced, depending on circumstances I haven't been able to identify yet.

The files I have uploaded prove that the amount of banding can vary a lot between two images of approximatively the same scene, taken at the exact same settings, processed in the same way.

This is an example of what it looks like at worst :


Please note the image is not pushed more than +1EV in post. Sharpness and NR are at default LR settings. The data in the squares is still in the midtone overlapping area.

The "problematic" photo (IMG_2241) can be downloaded from here: https://www.amazon.com/clouddrive/share/Lgdteww54UwrLw9nu2dSTIEssKthsQEf7KPOftGkHvH?ref_=cd_ph_share_link_copy
The other two photos in the link (IMG_2240 and IMG 2242) are taken before, respectively after the problematic one – and they seem to be much less affected by banding – but still, some horizontal banding is noticeable, especially in lower area of the sky.

The DNG conversion was done using the Dual ISO Converter LR plug-in, 3.0-BETA3 for Mac. I have tried all the possible setting combinations, nothing seems to make it better (except no-fullres, for obvious reasons).

I tend to think there is a problem with the converter, but I might be wrong. If any of you can download the files and convert them, I'd be really grateful :)

Thanks in advance for any input!
Some of 5D II and 7D have a maze pattern. That together with Dual ISO may perhaps give a different look?



The picture is from my 7D without Dual ISO.

bodhidharmazen

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Re: Banding when using Dual-ISO
« Reply #5 on: December 29, 2018, 07:46:19 PM »
Some of 5D II and 7D have a maze pattern. That together with Dual ISO may perhaps give a different look?



The picture is from my 7D without Dual ISO.

Its different, that is the noise floor of the sensor, while in the case of the banding problem is the poor job in intercalating the lower and higher iso images.