x100 What am I doing wrong?

Having a rail to brace against is great, but you can still introduce shake just by triggering the shutter. In this shot, I braced the camera itself on a wall, but it was tilted in order to frame it, so I still had to hold onto it rather than let it sit there. I used the self timer instead of just triggering the shutter. Note that I dialed in minus 1 1/3 stops EC as opposed to your setting of plus 1/3. I was able to use ISO 250 this way. Mouse over to see other EXIF data.