I just discovered that using Sigma Photo Pro 6 and saving settings to the X3F file modifies the X3F file so that SPP 5 can no longer work with it.
Ditto for RawDigger: it appears that the change is a re-save in a new file format. Writing over an original is bad enough (carries a real risk of data loss), but to rewrite the file format and make the file incompatible is a serious matter.
Worse, SPP 6 won’t deliver the color I want with Sigma DP2 Merrill files (something is badly wrong both for viewing files and for saving them in terms of color spaces). But I’ve figured out a workaround flow.
I want to be clear that I think the camera (dp2 Quattro) has huge potential for image quality. To my eye, it outperforms the Canon 5D Mark III for image quality. It’s the Sigma Photo Pro software that’s the issue.
SPP 6 also gets the prize for the world’s slowest and most buggy raw converter, by an order of magnitude. I still cannot use it on my Mac Pro, because opening an image for editing opens a window somewhere off both screens, out of sight and inacessible. And believe it or not, SPP 6 is *still* a 32-bit program on OS X, years after virtually every program on the market is 64-bit. If it continues to work in OS X Yosemite it will be a surprise. Might be a good idea to shoot RAW+JPEG. It’s also a very serious long term concern for anyone archiving X3F files for future use.
UPDATE: for whatever bizarre reason, placing the folder containing the images onto the desktop offers a substantial speedup for some operations. This was a suggestion from Sigma.
UPDATE 2: I expect a version of SPP with some bug fixes soon.
SPP 6 also has the curious behavior of displaying a great-looking JPEG at retina resolution on a 4K display—until it processes the raw mañana, at which point it does not support high-res displays, and the image now looks awful at its pixel-doubled blur.
Update: I’ve discovered a process that is totally wrong and nonsensical, but ultimately delivers a TIF that looks just like a camera-generated JPEG in terms of color. SPP is completely and utterly broken in terms of color management, so one has to look for ad-hoc workarounds. Not that SPP 5 worked for color management either.