I have some tabletop work to do which requires fairly precise exposure and color calibration to achieve consistency across a range of exposures and subject matter.
For this purpose, I did meter calibration testing with a triple target (white, neutral gray, black) and color calibration with a Macbeth Color Checker/Xrite Passport software. The results ...
- For raw capture, I found the meter calibration at ISO 200 is approximately .5-.7 EV optimistic and setting +.7 EV puts the exposure calibration test right on the calibration marks. This is a very common adjustment with most cameras: JPEG capture has less 'headroom' than raw capture so if the meter calibration is right on for raw capture, JPEGs will be overexposed. This supports what I've found in empirical observations of my photos made with the A12 camera units ... +.3 to +.7 EV Compensation generally nets the best original exposure. It's something you can experiment with to find what works best for your photography and raw processing workflow.
- What's striking about the Color Checker/Xrite Passport custom camera calibration is how very very close it is to the Adobe Standard camera calibration or the DNG file's embedded calibration profile. I ran the calibration with an exposure made at 0.7 EV Compensation in the same light as the metering check above ... the white and black point values are right where I want them for either camera calibration, the differences in the color swatches are very very small, within 2% points of RGB for all the Color Checker swatches. This is far closer to the Color Checker mark for reproducible accuracy compared to any other camera I've calibrated for this lighting setup.
I continue to be thoroughly impressed at how good a job Ricoh has done with the GXR.