It's definitely still true, but the difference is getting smaller as sensor tech improves. My DSLR is a Nikon D80 from 2006. While it's not full-frame, its sens

It's definitely still true, but the difference is getting smaller as sensor tech improves. My DSLR is a Nikon D80 from 2006. While it's not full-frame, its sensor is much bigger than the one on my iPhone 8, yet my phone works far better in low-light conditions. The highest non-expanded sensitivity on the D80 is ISO 1600, which is already very grainy. Bump that up to the highest possible ISO 3200 and you're in for a lot of touch-up work.