Two Issues with Xtrans RAW files

[tomczak]

I've been playing with Xtrans files from Fuji X-E2 in PWP RAW lately. It compares quite well with in-camera produced JPGs at any settings. But there are two issues I came across:

1) PWP RAW doesn't automatically correct for purple fringing on edges, which is understandable given hundreds of cameras it can support. Using Defringe presents two challenges: one is that the preview does not default to 1:1 that re-centres on clicking of the input image (unlike other transformation for which jumping form place to place in 1:1 is also required: e.g. chromatic aberration, all sharpening methods). The other is that while it removes the fringes efficiently, it often silently decolours small colour details of hue similar to the fringes throughout the image - and this is hard to see until afterwards. The only think I can do to prevent it is to mask everything, except for the fringes first (which is not that easy to do). One idea that I figured would help would be a warning system - something akin to AS before and after change map, or bright warning map indicating what is affected, so that I can adjust the transformation with confidence that only fringes I'm after and no other image elements are affected.

2) While I like PWP RAW details in the developed X-trans files, I'm not too fond of the default colour palette it produces. It is not so easy to correct it competently in RAW or afterwards - WB and colour balances affect the whites and grays as well. What I do now is extracting one of Saturation channels and use it as a mask before colour adjustments: http://www.dl-c.com/board/viewtopic.php?f=5&t=933#p4702. A slider or two doing the same thing in RAW and/or in Levels and Colour, would be much more convenient. Would it be a good idea?

Cheers!

[den]

Thought I would belatedly comment...

Here are two illustrations of X-Trans RAF file dcraw9.22 -v -w -H2 -o1 -g2.4-12.92 -6 -T conversions shown on the left and on the right is their reduced sized embedded jpegs zoomed to a comparable image size for illustration...

First... ...Fuji X-Pro1...

Fuji_X-Pro1_raf_dcraw_conv_and_embbed_jpg.jpg (61.97 KiB) Viewed 2071 times

Second... ...Fuji X100T...

Fuji_X100T_raf_dcraw_conv_and_embbed_jpg.jpg (79.28 KiB) Viewed 2072 times

For both illustrations note particularly the red and green fringes at major edges for the raw conversion and that this is greatly reduced in the associated jpeg files as well as the interpolation artifacts.

Utilizing dcraw's provisions for Chromatic Aberration reduction, Wavelet Noise reduction, and Median Blurring to reduce color noise will generally add saw-tooth like artifacts to the major edges... ...so the red/green fringing and interpolation artifact reduction will have to occur in post-dcraw algorithms in a third party conversion/editor software workflow on the dcraw conversion tiffs...

...this then becomes a special case for PWP's Raw Dialog for X-Trans sensor conversions as it is based upon dcraw raw conversions... ...the insufficiency perhaps is not with the PWP algorithms but perhaps with dcraw's upon which PWP's Raw Dialog and transformations are based...

Were I to have a Fuji X-Trans camera, I most likely would shoot RAW+JPEG at highest resolution, using PWP to edit the JPEG reserving the RAW conversion for when Exposure recovery, Color Balance recovery, etc. are needed... ...using the bundled SilkyPix Raw Converter that comes with the camera.

...den...

P.S. I am so tempted in the case of the X100T...! ;-)