Nexus S camera crop factor and angle of view
Judging from sample shots, angle of view of my Nexus S camera is approximately equal to that of 21 mm on my DSLR. Given DSLR crop factor of 1.52, it is as 32 mm in 35mm equivalent.
As I know that focal length f = 3.63 mm, the crop factor of the phone camera in Nexus S is approx. 8.8. Assuming 4:3 sensor, I estimate it is 3.9×2.9 mm. Pixel density is 44.2 MP/cm².