Someone on DPReview brought up this question:

Anyone else noticed the difference in color rendition between the A12 50 and A12 28 modules? ...

Color in digital photography is all a matter of rendering choices. I generally only use raw exposures.

The question inspired me to do a quick'n'dirty test which I hadn't done before ... comparing capture of an Xrite Color Checker with the two A12 modules against my Oly E-5 and E-1 bodies.

Setup was the same for all: indirect mid-day sunlight in my office. I check exposure with all four pairs using a tri-band exposure test target, placing the middle gray exactly in the middle on the histogram (those are the EV compensation values). All exposures were at ISO 200, auto-white balance. All exposures were made JPEG+raw.

All exposures were brought into Lightroom and processed at the defaults. All were cropped to the Color Checker and the chromatic aberration correction for each lens applied. No other processing.

By this crude test, the A12 28 and 50 camera modules seem pretty closely matched, the E-5 is fairly close, the E-1 renders more warm-toned images. It's interesting that the JPEG renderings on the Ricoh exposures were close to the edge of blowout where the DNG captures were right on the mark.

Not a definitive test of anything, but it informs me as to what to expect in shooting with these different sensors on the defaults.

I've now made upwards of 3000 exposures with the GXR, 1000 of which have survived past first cut pick and grade and are in my Lightroom catalog. It is proving to be an excellent camera for me.