When Nokia first introduced the Lumia 1020, people were quick to notice that the output colors produced by the new 41 megapixel PureView sensor was visibly oversaturated, and even noisier when comapred to the same 41 MP snapper in the Nokia PureView 808 (Symbian Belle). This was a result of changes made in the oversampling algorithm, in an effort to output images which looked more pleasing to the eye, but did not represent natural colors. That, didn't go well with mobile photography enthusiasts who lashed out at Nokia for taking such a step.
Good news is, the Finns have realised their mistake and are reverting back to the original image processing algorithms. The Lumia 1520 already produces natural looking images, and other PureView equipped Lumias will do so as well after they receive the Windows Phone GDR3/Nokia Black software update sometime later this year.