There is a white paper by Sony Semiconductor on the imaging processing which I think is in the HX1, //www.sony.net/Products/SC-HP/cx_news/vol55/pdf/featuring55.pdf. I assume it is the IMX-032 CMOS sensor (//www.sony.net/Products/SC-HP/cx_news/vol55/np_imx032cqr.html) mated to a CXD4109AGG image processing chip. There seem to be some interesting techniques employed, multi-plane synthesis to combine several frames for low light and HDR capture.
With the IMX-032, it is interesting to note that the on-board programmable gain amplifier has a gain value of up to 18dB or a factor of 8, so if base ISO is 80, then maximum “analogue” ISO is 640. If we compare the IMX-032 versus Sony’s first column ADC CMOS chip (IMX-017), the IMX-32 has an 11.8% better photo-electron efficiency per unit area (2300e per 1.75 micron square pixel compared to 4500e per 2.5 micron square pixel). Might be a sign that Sony is improving the process and design used to make their CMOS chips.
The backside illuminated chip is called the IMX-061, //www.chipworks.com/uploadedFiles/Aliased_Pages/CMOS_ImageSensors_Spotlight/Chipworks%20-%20Sony%20IMX061%20EXR-0902-813.pdf
6MP and 1.75 micron pixels in ClearVID (45 degree) layout with a 1:6:1 RGB Bayer filter array, sacrificing colour resolution for spatial resolution.
The Nikon D90 chip is called the IMX-038 (not the IMX-021 as for the A700), so this suggests it has significant revisions compared to the IMX-021 (possibly linked to LiveView and HD Video?).
– Dr Daniel K. L. Oi