I have been using my Olympus OM-D for nearly a year, and I have shot thousands of pictures with it, but how many time did I actually made use of the ISO 20,000 setting for really low light capture? ONCE!!
This still life test shot was taken in early May last year, while I was testing my newly acquired dream camera. It was shot at ISO 25,600!
Even at that never heard of (a couple of years ago), ultra high ISO for a HALF FRAME sensor, the result was ACCEPTABLE!