I was taking pictures and testing a few things at the local Blues and Country Music festival last week.
Once I had a few shots at the normal ISO settings I tried a few at ISO 800. People say the M9 starts to break up around ISO800 but I thought it worked well.
This first one is the full frame image while the other two started that way but were cropped into better images.
It wasn't really dark yet, and the artist was in open shade with a lot of even light on her and a drop of more direct sunlight right at the bottom. I think the images hold up well, even with the crop. They're not quite as clean as the shots at the lower ISO but the colour still looks good and the tones in the guitar look fine.
They were done on the Zeiss 85mm f4, stopped down a couple stops.
My retail store for rangefinder photo supplies is http://www.rangefinderstore.com/