The adaptive lighting feature will automatically switch on the built-in flash on iOS devices in dark spaces such as storage rooms and basements.
Therefore an external light source is not needed anymore. It is still highly recommended to switch on all possible lights to get the best results.
Please, bear in mind that some iPads do not have flash, hence, this feature is not available for them. Here is a list of devices that do NOT have flash:
iPad Air 3rd generation
iPad 5th generation
iPad 6th generation
iPad 7th generation
iPad 8th generation
iPad mini 5th generation