>>4004772But then it's the aperture that's changing the DoF, not the light itself
You also get "more light" by increasing the ISO, but that won't help you get a shallower depth of field
Low light is when you'll be needing a wide aperture the most, hence is when you'll be dealing with shallow DoF
But the explanation is that when the cone of light is larger, the plane of focus is shorter, and when you close the aperture and make it smaller, the plane of focus gets longer, augmenting the DoF
