PhaseOne P 65+ User Manual page 17

Power management and shutter latency
The CCD on the P65+ back needs to be cleared before an exposure.
This requires some power consumption.
Deafult is Normal Latency, and this should be kept, under all "normal"
situations.
Change the latency to "zero latency" only if you work on technical
cameras, large format cameras or certain manual cameras in special
situations if using "one-shot" cable release. - Please see the section
specific for your camera body for more information on what latency
setting to select.
Zero latency will lead to an significantly increased power consumption,
therefore it is highly recommended to use your computer as powersource
when running on Zero latency instead of using the battery.
Double exposure protection
It is not possible to accidentally double expose the image by capturing
one image quickly after another when the P 65+ back is used on i.e.
Phase One 645AF, Mamiya 645 AFD/AFD II/AFDIII, Hasselblad 555 ELD
(DIG mode), Hasselblad H or Contax 645.
The electronic communication with the body ensures that the P 65+
back is ready before allowing release of the next shot. On other camera
bodies not using the electronic interface from the P 65+, the user has to
wait for the ready beep signal before releasing the next shot.
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