I recommend watching this video for starters. You can also see the size of the sensor and Zeiss optics on the video.
Originally Posted by ubizm0
There's also plenty of camera blogs and such analyzing the camera in detail. It really is in it's way set to revolutionalize below 600 euros cameras.
In short, yes, you can take 38MP pictures on the 41MP sensor. We have seen those pics and they do look amazing, BUT the innovation here lies on the oversampling, megapixels on the sensor and how those megapixels are used.
On 5MP oversampling mode (this mode is in default when you open the camera) you are taking 7 pixels on the sensor and uniting them as one with you having one huge pixel that naturally takes much more light in it. Binning is something similar to this, usually found on the plus 1000 euros DSLR's. Nokia says that because of the much higher calculating power and Nokia's algorithms on 808 it can take it to another level on PureView with the oversampling.
Another point that this megapixels bring to the table is lossless zooming live when you are video recording or taking a picture, the point not really being that you crop the picture after taking it, while you can do that as well if you are taking those 38MP shots.
808 of course has it's own GPU on the SoC, but the camera module itself actually has another GPU inside. Screens are always the most expensive part of the phone... i wonder if that's the case with 808 PureView.