Luminous Landscape Forum

Raw & Post Processing, Printing => Other Raw Converters => Topic started by: biker on February 20, 2016, 05:46:09 pm

Title: Darktable vs. RawTherapee - Moire Reduction Test
Post by: biker on February 20, 2016, 05:46:09 pm
Here is a moire test sample image photographed with a camera without an AA filter (Nikon Coolpix A).
The pictures are crops from the original image (16 MPix APS-C sensor).

part1.jpg (from top to bottom)
- original camera JPEG (fine)
- darktable Amaze
- darktable PPG
- darktable VNG4

part2.jpg (from top to bottom)
- RawTherapee AHD
- RawTherapee Amaze
- RawTherapee DCB
- RawTherapee EAHD

part3.jpg (from top to bottom)
- RawTherapee Fast
- RawTherapee HPHD
- RawTherapee IGV
- RawTherapee LMMSE
- RawTherapee VNG4
Title: Re: Darktable vs. RawTherapee - Moire Reduction Test
Post by: sankos on February 23, 2016, 02:42:12 pm
So what are your conclusions?

In my raw converter tests for the Coolpix A I found that the Capture NX-D is quite good at reducing moire (possibly slightly better than RT with amaze). Another good converter for that is DxO Pro, but you need to watch out with this one because its Moire and CA removal defaults are colour-killers (and it is actually the CA filter that takes care of the moire, from what I've seen). Capture One is another good moire remover. LR, my go-to raw converter for the Coolpix A, is actually quite bad in this respect -- you need to take the brush and apply corrections manually. The most atrocious raw converter for moire is Silkypix DSP7 -- I've no idea how they did it, because the NX-D is just a rebranded and simplified SP, and yet SP7's moire correction is almost non-existent.
Title: Re: Darktable vs. RawTherapee - Moire Reduction Test
Post by: biker on February 23, 2016, 04:24:39 pm
I've added the original RAW to OneDrive (http://1drv.ms/1KI0dT9). Just right click the icon a download the .NEF file.
I'd be interested to see results of those commercial RAW development programs, if possible. Without any manual retouching, of course!

Please ignore the mess around the sample image. :-[

To crop developed images, you can use Image Magic like this:
Quote
convert -crop 1164x834+1870+1275 DSC_0043.tif cropped1.tif
To make a vertical set from cropped images:
Quote
convert -append cropped1.tif cropped2.tif cropped3.tif -quality 95 target1.jpg
Or, you can do it manually...

So what are my conclusions?
Based on my original samples, nothing really helps.
Camera JPEG seems to be the least coloured one, but at the cost of sharpness.
Darktable Amaze is a bit sharper with a bit more moire.
RT Amaze would probably be the third best - even sharper than darktable with a visibly stronger moire.
Title: AMAZE is best for Coolpix A
Post by: sankos on February 24, 2016, 09:23:24 am
So, I've downloaded your raw file and converted it in 7 converters on the Windows 8.1. Since the defaults are vastly different for each of them I've decided to apply a different methodology -- getting the most out of each of them with respect to detail and optical corrections (subjective, I know). I cropped inside each converter and developed the file to 8-bit, uncompressed, sRGB tiff (no output sharpening added). Then I opened them in PSE and saved as quality 10 jpegs (so as to avoid jpeg compression discrepancies between the converters). Here are the conversions:
https://www.dropbox.com/sh/h1qp90hvrf37ek4/AABYcdKoh4neJe5wsy5EJGNBa?dl=0

My notes (list sorted by quality):

My conclusion: AMAZE is the best demosaicing algorithm for low ISO photos from the Coolpix A.
Title: Re: Darktable vs. RawTherapee - Moire Reduction Test
Post by: biker on February 24, 2016, 02:40:12 pm
Thanks for your research! It's difficult to judge but Amaze indeed seems to be the best moire killer and fine details keeper at the same time.
As for SilkyPix - I tried it (the FujiFilm specialised version!) for developing my X-Trans sensor RAWs and results aren't very good also in this case. While colours are almost the same like in camera JPEGs, the demosaicing introduces ugly artifacts on surfaces that are perfectly clean in camera JPEGs.

Back to Nikon Coolpix A. I'm adding a few more results, created by UFRaw (http://ufraw.sourceforge.net/).
-UFRaw AHD
-UFRaw Bilinear
-UFRaw PPG
-UFRaw VNG
-UFRaw VNG 4 colours inerpolation
All of them (compared to Amaze) are rather pathetic.