The GG01 calibrated ground glass is a replacement for the ground glass supplied with the view camera for shooting with film.  Using the new ground glass it is possible to compose an image using the full 6cm x 12 cm scanning area supported by the SB01 adapter.  

It is also possible to accurately control the movements of the view camera for correct focus and depth of field using the ground glass.  The recess in the ground glass is accurately set to correspond with the location of the image sensor built into the DSLR body.  This ensures that the image plane is consistent between the ground glass, and the capture device.