48MP works badly in low light as each individual pixel size is small.
The sensors from SONY are designed to work best in 12MP , where 4 pixels are combined for color data.
48MP is generally only suitable/recommended in bright daylight - as you need a lot of light (to counter the small individual pixel size) but also fast shutter speeds to counter the longer processing time. Keep in mind the ZenFone 6 does not have OIS.