lcalamar Correct - the GOS camera does not provide the 4x optical zoom feature that the P6P has.
P6P DOES NOT HAVE OPTICAL ZOOM
Optical zoom means a lens that actually moves in order to change zoom.
What P6P has, is 3 distinct camera sensors. 4 if you count the one in the little hole in the screen.
One of the differences in the 3 cameras is the magnification of the lens associated with them. If you're looking at the back of the phone, the first lens/sensor you see is the main, then next over is a lens with a wider angle, and the third one in the rectangular hole is more zoomed in.
The HAL on P6P switches between sensors dynamically as the level of zoom and other conditions change. Typically, it will switch to the zoomed in lens at a magnification of about 4.5x (not 4x -- google camera mucks around with the numbers, the real number is higher). Make sure that there is adequate LIGHT and that your scene is far enough away that the camera can actually focus!
Works like this; at 1.0 it will use the MAIN sensor. As you "zoom in", it will apply digital zoom (combination of cropping and scaling). When it reaches the threshold for the next sensor, it will switch over to it at NO digital zoom, then as you continue to zoom in, it will apply digital zoom to that as well.
IMO its a kind of a fraud. Scaling kills image quality so shouldn't be used. Even cropping is annoying. It would be much nicer if we could distinctly select each sensor and then decide if we want to use any crop/scale.
You can usually see a slight visual "jump" when it switches, but to know for certain, put your finger over the different lenses, then you can tell which one it is actually reading from.
I can promise you that GrapheneOS will use ALL of the different sensors available on P6P.