The Xiaomi 17 Ultra features a large 1-inch sensor, whilst the Vivo X300 Pro’s sensor is smaller but has a wider aperture and offers both gimbal image stabilisation and CIPA 5.5.
The focal length is slightly longer at 23 mm on the Xiaomi, whilst the Vivo uses 24 mm. Both allow other standard focal lengths for the main lens via in-sensor zoom, provided pixel binning is active. These can be easily switched to the standard zoom factor within the camera app by simply tapping, but on the Xiaomi they can also be fixed in the settings. The 17 Ultra offers a choice between 23, 28 and 35 mm, whilst the X300 Pro offers 24 or 36 mm.
The results vary considerably. Particularly in daylight, we find the colour balance of the X300 Pro to be more successful, as the 17 Ultra often brightens the subject significantly. In the dark and in low light, however, the Xiaomi smartphone really comes into its own, delivering both a more balanced image and greater detail. The Vivo tends slightly towards overexposure here, attempting to artificially increase the dynamic range.
Whilst we would generally lower the exposure value slightly on the 17 Ultra (-0.3 to -0.6 EV), we recommend doing so on the Vivo smartphone mainly for dark environments. Both can save the settings permanently, though the Vivo can only do so in Pro mode.