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Specifications of Foveon X3F files

Started Jan 11, 2017 | Questions thread
OP james123 New Member • Posts: 21
Re: What about Kalpakana?

Kendall Helmstetter Gelner wrote:

At this point your best bet is probably to examine the Kalpakana source, which can handle modern files:

Yes that's what I called doing reverse engineering on x3f tools. And that's what I finally did yesterday. It's interesting, and it mainly shows that the Foveon files contain a plethora of informations regarding the handling of the colorimetry, much more than any other raw files I have decoded in the past.

Moreover, I have compared the output of x3f tools and dcraw to the output of SigmaPhotoPro, and SPP is definitely able to perform some magic, not regarding resolution, but regarding colorimetry, that dcraw and even x3f tools are unable to perform.

I tried different workflows, either generating 16 bits DNG, or generating linear unprocessed 16 bits RAW PPM data, and then adjusting gamma and colour balance in Photoshop, to no avail in either case. This is especially true in "blown out" areas where SPP is able to recover a lot of dynamic while x3f/photoshop can't without displaying nasty colour artefacts. There is an example below where you begin to see a nasty green artefact on a white wall facing the sun (the complete shot was a difficult one, with shadows and highlights).

Sigma Photo Pro

x3f tools+photoshop

Below the complete shot:

Full shot, with SPP

The bottom line is that you can't get rid of SPP in your workflow, at least for the SD1, which is bad news...

SPP is able to perform tricks that other softwares can't, and I am beginning to understand why the SD1 is still not supported by Adobe Camera Raw, while the SD14 and SD15 are...

PS: don't get me wrong, I love the images that I can get with the SD1. DPR said that they are "intoxicating" and I fully agree. It's just that the ecosystem around that camera is really poor, and it's a pity sigma is not willing to share more tech info with the public; this could have helped in developping free tools around this wonderful camera.

 james123's gear list:james123's gear list
Canon EOS-1Ds Mark II Canon EOS 5D Mark II Canon EOS 450D Sigma SD14 Leica M9 +1 more
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