Summary
A viewfinder mask is to be used, mount it under the focusing screen. Flash cables connects to the body not the back.
In-Depth
The image area of the Hasselblad H Camera System is approximately 6cm x 4.5cm. However several digital backs have a sensor that is smaller than that measurement and require a viewfinder mask to provide an accurate reference when composing an image.
When you purchase a Phase One Digital Back the thin reference mask is provided. This mask has to be mounted below the focusing screen. The viewfinder mask is positioned in the bracket that holds the focusing screen.
Mounting the P/P+ Back:
The H mounted backs (both H, P/P+, and IQ series up to and including IQ3) integrates fully with the H camera body and acts as a part of the whole camera system.
When no cassette is attached to the Hasselblad camera body the mirror is up and the shutter is open.
When attaching the Digital Back to the camera body the shutter will close and the mirror comes down.
It is important to ensure that the bottom part of the H mount camera back is pressed well into the locking mechanism before the upper locking mechanism is pressed together.
Use of cables
No cables are required between the H Mount Back and the Hasselblad H Camera system.
When using a Flash system and connecting it directly to the camera a Flash sync cable must be connected to the Hasselblad H camera body. The flash sync cable must NOT be connected to the camera back when used on a Hasselblad H Camera system. The flash sync connector on the Camera back is only intended for use with a Phase One FlexAdaptor, or other large format adaptors.