Author Topic: remaining stripes after cr2hdr postprocessing (5DmkIII ISO 100/6400, auto ETTR)  (Read 2732 times)


  • New to the forum
  • *
  • Posts: 3
Dear ML-experts!
Your help is needed. I was having some fun doing a holy grail timelapse with ETTR and auto dualISO, which adapted ISO to be as high as 6400/100 in certain frames. I know this is a rather big dualISO difference, though I had no control over that, since it was automatically set by the ETTR function.

The trouble I encounter is with postprocessing: Whenever cr2hdr processes a frame that has a 6400/100 ISO difference the resulting frame still has some stripes not unlike the original dualISO frame, amd I can't figure out how to fix this.

Has anyone encountered a similar issue?


  • Administrator
  • Hero Member
  • *****
  • Posts: 12316
  • Emergencies only
Upload a CR2 (one that shows the worst artifacts, if possible).


  • New to the forum
  • *
  • Posts: 3
Here you go:

This is a link to my Dropbox with all the files of one of the timelapse frames with 100/6400 ISO. I passed it through the cr2hdr debug function, so there are also all intermediate .dng files.
The 8H5A1511.CR2 is the original and the 8H5A1511.DNG is the standard output from cr2hdr.exe

Here is the debug log:
Code: [Select]
C:\Users\******\Desktop\cr2hdr_co>cr2hdr "F:\5DmkIII\Timelapse\2016-04-20_SG Moonrise Rooftop\8H5A1511.CR2" --debug-blend
cr2hdr: a post processing tool for Dual ISO images

Last update: ab1e90c on 2015-11-24 09:50:19 UTC by a1ex:
cr2hdr: moved safeguard from median_int_wirth to kth_smallest_i...

Active options:
--amaze-edge    : use a temporary demosaic step (AMaZE) followed by edge-directed interpolation (default)
--cs2x2         : apply 2x2 chroma smoothing in noisy and aliased areas (default)
--wb=graymax    : set AsShotNeutral by maximizing the number of gray pixels (default)
--debug-blend   : save intermediate images used for blending:
    dark.dng        the low-ISO exposure, interpolated
    bright.dng      the high-ISO exposure, interpolated and darkened
    halfres.dng     half-resolution blending (low noise, high aliasing)
    fullres.dng     full-resolution blending (minimal aliasing, high noise)
    *_smooth.dng    images after chroma smoothing

Input file      : F:\5DmkIII\Timelapse\2016-04-20_SG Moonrise Rooftop\8H5A1511.CR2
Camera          : Canon EOS 5D Mark III
Full size       : 5920 x 3950
Active area     : 5796 x 3870
Black borders   : 124 left, 80 top
Black level     : 2024
ISO pattern     : BddB RGGB
White levels    : 15166 13864
Noise levels    : 51.26 6.90 7.47 67.37 (14-bit)
ISO difference  : 6.00 EV (6400)
Black delta     : -11.96
Black adjust    : -72
Dynamic range   : 10.89 (+) 7.46 => 13.46 EV (in theory)
Looking for hot/cold pixels...
Hot pixels      : 456
Cold pixels     : 1562
AMaZE interpolation ...
Amaze took 2.34 s
Edge-directed interpolation...
Semi-overexposed: 6.45%
Deep shadows    : 92.38%
Horizontal stripe fix...
Full-res reconstruction...
ISO overlap     : 3.0 EV (approx)
Half-res blending...
Chroma smoothing...
Building alias map...
Filtering alias map...
Smoothing alias map...
Final blending...
Noise level     : 579.06 (20-bit), ideally 48.36
Dynamic range   : 10.50 EV (cooked)
Black adjust    : 56

AsShotNeutral   : 0.44 1 0.95, 8641K/g=1.41 (gray max)
Output file     : F:\5DmkIII\Timelapse\2016-04-20_SG Moonrise Rooftop\8H5A1511.DNG
F:\5DmkIII\Timelapse\2016-04-20_SG Moonrise Rooftop\8H5A1511.DNG: copying EXIF from F:\5DmkIII\Timelapse\2016-04-20_SG Moonrise Rooftop\8H5A1511.CR2

Thank you!


  • New to the forum
  • *
  • Posts: 3
Upload a CR2 (one that shows the worst artifacts, if possible).

Hi A1ex, there's a thing I realised: in debug mode, the halfres (halfres_smooth.dng and halfres.dng) files seem to look just fine... But I guess there is some kind of downside to this, maybe like a loss in resolution?

Do you think I can just use those rendered "debug"-frames? And is there a way of batch-rendering them from some 100 .CR2-frames?


  • Administrator
  • Hero Member
  • *****
  • Posts: 12316
  • Emergencies only
Yes, some of these files have half resolution.

Until I'll fix it, you can also play with --no-fullres or --no-alias-map.