... is often done from completely different viewpoints:
If you compare it to typical vendor supplied software the conclusions are often:
- its OK or better than some other vendor supplied software
- it provides the best processing for Foveon files
- it fairly stable
However if you compare it to professional tools like Photoshop, Lightroom, or Capture One the conclusions are often:
- its image processing algorithms are tailored to the foveon chip, correcting for a number of known problems (e.g. cyan/purple splotches, green vignetting, banding noise)
- the x3f fill light is a tailored and improved version of the typical Shadow/Highlights tools that often yields better results (especially if you stay below an adjustment value of about +0.7) than whats available even in professional software tools
And here are my negatives:
- colour adjustment and correction is lacking, especially for achieving a uniform adjustment across a series of shots (a very important point for professional work), i.e. there are no absolute colour settings reported or adjustable (such as the temperature and tint values in Photoshop), SPP only has relative settings with respect to a base, and in case of AUTO, this base is different for each and every photo.
- the highlights tool is poor when compared to professional alternatives
- the range of exposure correction is too small (see last point)
- its chromatic aberration correction is poorly implemented and does not completely heed the characteristics of lateral chromatic aberration (see http://rftobler.at/Photography/TipsAndTricks/Aberration/ )
- sharpening lacks fine control
- speed is fairly poor: a lot of adjustments need a complete recalculation of the whole image, leading to delays if lots of photos have to be adjusted (again a problem for professional work). Although this can be migitated with a fast machine, the same machine will handle even a lot more complex adjustments interactively in professional tools.
- it is sometimes very hard to impossible to export a 16-bit tiff image that retains both all highlight and shadow information inherent in the foveon files without other damage. (Only the exposure compensation can be exactly reverted in later processing, and thus all other changes, i.e. highlight compensation and x3f fill tool, will significantly change colours)
My take on Sigma Photo, starting with the good points:
Note, that the judgement of stability, is very different dependent on where you come from: in professional software it is assumed that no problems occur just because you enter a directory with thousands of raw photos, or a used to quickly responding software. Thus an instability in handling such situations (which seems to be a common complaint with SPP) leads to gripes with the software.
- it very slow
- it doesn't provide good colour adjustment and correction
- chromatic aberration correction (useful for DP1M) is inadequately implemented
- it is very limited in functionality
- it is fairly unstable
Based on these observations, I sincerely hope that Michael Reichmann's public letter to sigma, will not fall on deaf ears, and we will eventually get support for DNG export (which can be done using the linear DNG option, without Sigma giving away all its algorithms) in Sigma Photo Pro or support for the DPxMs in one of the professional tools. For me, I will leave SPP behind as soon as either of this things happen... and it cannot happen fast enough
Phew... this turned out longer than intended, but maybe, just maybe, it cleared up some of the differences in perception of SPP.
Robert F. Tobler