I wanted to evaluate the Pentax 645Z image quality with long exposures for two reasons. First, medium format has often suffered with long exposures (most though not all cameras), and second, the 645Z establishes a reference for the Nikon D810.
I evaluate a 32 minute exposure with +0.4 stop push in my review of the Pentax 645Z:
Includes HD and UltraHD images in RGB and with the red/green/blue and gray gamma 2.2 channels and two large crops with same.
This test scene won’t last long as I have dibs on those blueberries.