Lollipop uses two kinds of IR LED.
The use of one or the other IR led depends on how bright the leds can illuminate whatever the camera is looking into, could be objects or the baby, for example. Also need to take into account how much other sources of light are there in the room, because those other sources of light will make the cam judge that the room might be too bright.
When it detects the baby or bed in a near field, the 940 nm wavelength IR LED (invisible to the human eye) is turnt on.
On the other hand if Lollipop is far away from the baby or bed, the shorter 850nm IR LED (visible to the human eye) will kick in for better vision.
There IR LED switches automatically accordingly to the environment.
You can try re-positioning the camera however there is no manual way to turn the red ring light off so far.
If the 940nm IR LED can't make the scene be bright enough, the cam is going to switch to the 840 IR LED.
If the 940nm IR LED can't illuminate the scene, it will switch to the other one and stay with the other one until there is enough light to switch to the 940nm IR LED or turn them completely off. The camera can't measure distance but it can measure how much light there is at whatever it is seeing.
There is no exact distance for this because objects around the crib or the vicinity of the camera might make the scene go too dark or too bright, like white curtains, the bars of the crib, bedding of the baby, sheets, clothes of the baby, etc.