In an attempt to ameliorate the a7R portrait-orientation vibration blur in the preceding post, I made two modifications to my setup. I cinched the lens to the support with a cable tie (shown before the ends were cut):
And I put a two-pound weight on the bottom of the camera:
The result was an improvement in the horizontal blur at 1/80 second:
but an increase in the horizontal blur at lower shutter speeds. In fact, the worst shutter speed became 1/30 second: