strong banding in cloudy sky regions

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strong banding in cloudy sky regions

Postby Erik Krause » Sun Jul 22, 2012 8:24 pm

I'm just experimenting with SNS-HDR lite 1.4.22 as a preplacement for enfuse. I found strong vertical banding at an 8 pixel interval in cloudy sky regions. Since it is very severe in slightly misaligned images I suspect this is simply due to misalignment. Source images are 16 bit TIFFs converted from EOS 5DII raw files. Parameters are -da -natural -tiff16. Using -dd sometimes improves the situation but only gradually.

Is this a known problem? If needed I can probably prepare a test case...

If this could be improved SNS-HDR would be the very first choice for all kind of bracketed shots.

best regards
Erik
Erik Krause
 
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Re: strong banding in cloudy sky regions

Postby den » Mon Jul 23, 2012 5:53 pm

Have you tried letting SNS-HDR Lite do the Raw conversion as well as the image merging and "-natural" preset tone mapping? Perhaps with the addition of " -n1" or " -n2" Raw noise reduction? [ref: http://www.sns-hdr.com/forum/viewtopic.php?f=7&t=352].
den
 
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Re: strong banding in cloudy sky regions

Postby Erik Krause » Mon Jul 23, 2012 7:00 pm

I tried that just for curiosity, but it causes the same kind of banding. -n2 reduces it a bit but it is still visible.

However, this it is no option for me anyway. I shoot raw because I want to correct for chromatic aberration (which ACR does perfectly). Moreover those are fisheye images and I shoot hand held most of the time. I need to align them using a program that is aware of the fisheye geometry (align_image_stack or PTGui). Hence I need to convert to TIFF first.
Erik Krause
 
Posts: 38
Joined: Sun Jul 22, 2012 8:10 pm

Re: strong banding in cloudy sky regions

Postby den » Mon Jul 23, 2012 7:37 pm

Thank you for the "try"... ...have no further suggestions re 'fish eye' lens geometry image data... ...but, like you, have observed with my own Canon EOS-350D normal lens CR2 files that if chromatic aberration correction occurs in the Raw conversion before sharpening/contrasts/color edits, that the SNS-HDR resulting image is much improved...
den
 
Posts: 100
Joined: Wed Sep 21, 2011 3:20 pm
Location: Birch Bay near Blaine, WA USA


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