The Sigma DP2m saves rather heavy-weighted RAW files that are not supported by leading RAW converts of today. Presuming you have already spent plenty money on your current software, it’s likely you’ll make do with the free Sigma Photo Pro 5 software not supplied with your camera, but available for download online.

In the past, Sigma Photo Pro (SPP) has a reputation for being a virtually unbearable piece of software, but the versions have improved quite a bit over the years. My first experience with SPP 5 was very early 2012, when I first started to look at SD1 RAW samples. I don’t recall which version it was, but back then, the software was excruciating and almost unusable on my mac. While a lot has changed since then, the latest version of SPP (V 5.5.2) is still not incredibly reliable or fluid. Working through 70 to 100 odd images would result in about 3 to 20 “unexpected” crashes, a few complete freezes, the occasional error dialogue-box pop up, and lastly the need to restart the program every now and then to prevent very slow responsive behaviour. Besides this, the saved TIFF files show differences in black point to the image rendered in SPP, as well as the occasional difference in colour. I have therefore resorted to doing the absolute minimum in SPP 5, and leave the any critical editing for Lightroom or Photoshop.

One of the more important aspects in my Sigma DP2m image workflow, is to assign a colour profile calibrated from a Gretag Macbeth chart, based on a standardised colour output from SPP. For colour, I have set SPP to use the X3F settings from the camera, which I will always have set to Daylight WB and Neutral Colour Mode. Also, files from SPP will always be saved as 16bit TIFF files with the Adobe 98 colour space. Based on this consistency, I created a calibrated icc profile from SPP’s output, which I then assign to my images using Photoshop, achieving greater accuracy in colour images. The results so far have been very good, and are far more pleasant than SPP’s output. A precaution one needs to take when using this method, is the possibility that with every camera firmware update, or SPP software update, that colour may be altered in some way or another. It’s therefore advisable to create a new profile with every software update or camera  firmware update. Users may have noticed a few changes regarding colour and WB when updating camera firmware V 1.04 to 1.05.

For  those interested, I used an application Called CoCa, an open source windows executable program that creates ICC profiles for digital cameras and scanners, supporting various standard colour calibration targets. One can run CoCa on the mac using Wine, or even more surprisingly have it create a self contained stand-alone Mac application of CoCa.

Below is an image-slider comparison between the standard SPP output (left) and the calibrated image (right). While the comparison below doesn’t show a dramatic difference between the two images, it does show the differences in rendering of blue skies, which is something that bothered me with SPP’s output.

The Image Editor:

Some of you may have notices that SPP’s colour output is somewhat “enhanced” with something that resembles the tonal adjustments of a pseudo-HDR effect, creating stronger tonal contrast over a localised radius of pixels.  This silent “enhancing” might be beneficial for many images, but it annoys me tremendously at times. When shooting portraits, where the rendering of skin tones is important, this “enhancement” tends to make the subject look 10 years older!

I came across this purely by accident, while switching from Monochrome WB in the Colour mode to the Monochrome mode. This pseudo-HDR look often emphasises noise, since it lifts shadows and darkens highlights relative to the radius over which the effect works (I’m guessing the radius is around 10 or 15 pixels).

To avoid this effect, but still have colour output, there is yet again more work ahead for your Sigma DP2m workflow. You’ll need to save both the colour and the monochrome versions of the same image, open these images as layers in Photoshop, set the colour image to be the top layer, and change it’s blending mode to “colour”. Appropriately, change the monochrome layer’s blending mode to “Luminance” if it’s on top of the colour layer. You could of course purchase Iridient Raw Developer, which doesn’t have this pseudo-HDR effect.

Below is an image-slider comparing the original SPP output (left) with the corrected image (right). Below that image-slider is another image-slider, comparing a scene taken in the dunes. Again, SPP output on the left and the corrected image on the right.

Notice the increase in global contrast of the corrected image, since the pseudo-HDR effect isn’t pushing the shadows and pulling the highlights. The second comparison shows how the original image, especially in the sky, is more grey and dull compared to the corrected image.