I have a question, some says that two different Android smartphones with the same sensor have different picture quality because of the software.What do they mean? The software, in this case, it's a camera app or something low-level, OS specific, drivers etc? I totally understand that the camera great in a smartphone because of: lens, sensor, pixel size, ois and software. So what is software in that case? Thanks
Camera does not give you the raw data it captures. Before it outputs the format you desire, the data will be processed by a set of algorithm implemented differently by each manufacturers, giving effects such as sharpening, denoising and anti-Moire. How they decide to implement it is beyond our discussion.
Manufacturers keep the algorithm private, so in many cases it's unclear whether it's only in the drivers (blobs) or requires both the app and the low level to work together. However, it's clear that without these proprietary algorithms, image quality will degrade more or less, as evident in custom ROMs without the camera blobs. In Sony's case, that algorithm can also get lost once you unlock the bootloader, causing equally significant effect.
The software controls the camera settings like aperture, exposure, iso and also autofocus. So if the software sets wrong settings or just uses settings which aren't perfect and another software uses better settings, you get a different image quality with the same camera.
The same counts for manual camera settings. If you configure your camera wrong, you get imperfect pictures.