Quote: you can bump up the ISO on the FF sensor by 1 stop compared to the APS-C sensor and have similar DR/noise.
APS_c------------------- FF
IS0 100...................ISO 200 - DR and noise are equivalent
1/100s....................1/100s - shutter speed is equivalent
ƒ2.8........................ƒ4 - total light used by the sensor to create the image and DoF are equivalent.
These images are roughly equivalent (ignoring the 1/3 stop) . There is simply no FF advantage. What you gain in DR and noise, you lose to maintain depth of field, should you choose to go that route. The fact that many have been deluded into thinking equivalence gives an advantage to one format or another is pretty crazy. What FF does allow you to do is to accept less DoF for better noise/DR performance in the rare instance where less DoF is acceptable, should you wish to make that trade. The fact that many have bought into FF based on a mis-understanding of the science is irrelevant.
FF gives you more total light, and higher ISO if (and only if) you are willing to accept less DoF(and at most ƒ stops, APS-c gives you the same trade off, only shooting wide open is there an FF advantage.) . If DoF remains the same, all other features remain constant . That's equivalence. You have to go to extreme measures, as in the article you posted, where they took some really bad low light images, to demonstrate any difference at all. And even then APS_c and FF were practically identical. Sometimes the articles people post, in support of their point, don't actually support their case, as in this one.
The reason they had to use a low light image to show any difference at all, was because they know the difference at high high iSO is minimal to start with. The difference between 100 and 400 ISO on APS_c is minimal, so no one cares if you're shooting 100 or 200 or even 400 ISO. Both on the test charts with their little graphs etc, there is simply no discernible difference. between APS_c and FF until 800 ISO, so between 100-400 ISO, there is simply a theoretical difference, that doesn't actually affect real world IQ.
Or as I've been saying for years, an FF can make a really bad image, less really bad, but it in no way implies you can't get equivalent images with APS-c 90% of the time if you are shooting high quality images.
I feel really sorry for the people who bought into FF expecting really amazing low light images, or even marginally better images. You will get some better images. But in many cases you'll be lugging around heavier more expensive equipment to get the same image.