On Latest version firmware G965FXXU7DTAA/G965FOXM7DTAA/G965FXXU7DTA3
with Android 10 (One UI2.0) there is an issue with switching to telephoto lens.
On Android 9 level of light was measured through Telephoto lens which was then used in sufficient light conditions.
Since Android 10 this measurement is taken via Wide lens first and only if it seens enough light it will switch to Telephoto lens. Not only that this is slower but it also makes it impossible to use addon Telephoto lens such as Moment 58mm Telephoto installed over Samsung tele lens (to achieve 4x optical zoom). Since the addon lens blocks 70% of the wide lens view, Wide lens will see pretty much only black screen and it will never switch to telephoto lens.
This seems to be a bug - please fix it....On a side note I don't really understand why Samsung does not switch to Telephoto at 2x zoom level every time. I cannot imagine any valid scenario when someone would want to use digital zoom before taking photo. it is just plain stupid since you can always crop or zoom photos after they are already taken. Even if someone would want to use digital zoom then they would probably go for something more then 2x anyway. So I think Samsung devs can force Tele at 2x zoom regardless of light conditions. Also underexposed footage is far better then blown up highlights - which is what we get without Pro mode video in low light auto.
This seems to be a bug in Camera app 10.0.01.49 - Samsung please fix this.
Or better let us use our TeleLens whenever we choose to and not only with Native camera app.