I just bought new Sigma 10-20 for making higher resolution spherical panoramas. Do You know how many images I should stitch to achive panorama minimum 20.000px x 10.000px ?
I will use NN4 and Canon EOS 60D at full resolution.
An easy way to work this out this is to add a few dummy images into PTGui and move them around in the Panorama Editor window, trying various focal length settings and setting the output size to maximum. 14mm gives you 20264x10132. The image fov at 14mm is 56.4°x77.6°. A yaw increment of 45° gives 20% overlap, so three rows of 8 at pitch +60,0,-60 will cover 360x180 nicely - plus a nadir shot.