The official Nokia Conversations blog published a post by Damian Dinning on the journey to the 41MP camera phone. Some quotes:
"the innovation and news is NOT the number of pixels but rather HOW those pixels are used."
"For some of our team, it’s taken over five years to bring this to the market..."
"After developing several optical zoom modules, we were still seeing significant performance trade-offs caused by optical zoom: performance in low light; image sharpness at both ends of the zoom range; audible noise problems; slow zooming speed and lost focus when zooming during video. We became convinced this could never be the great experience we once hoped. You’d need to accept a bigger, more expensive device with poor f no., a small and noisy image sensor and lower optical resolution just to be able to zoom."
"We had often debated that, for the vast majority, 5-megapixels completely fulfils their real world needs, but the market for many years has been pixels, pixels, pixels. It’s hard to block that out. Our friends at Carl Zeiss believed the same."
"This is, without doubt, our most complex imaging project to date."