Summary
Can I shoot tethered with the P 20 and P 25 using battery power?
In-Depth
Power requirements:
The P 25 and P 20 can be operated as fully portable units powered by the embedded battery and shooting to a compact flash card or micro drive which is inserted in the CF-card slot on the left side of the camera back.
Shooting tethered with these models requires the use of a 4 to 6 pin FireWire adaptor and cable if battery power is required. This is called the No-Firewire Power Adapter (Item No. 70508)
If the digital back is connected to an Apple Powerbook without this adaptor, it will drain the computer's battery and possibly lead to images with lines showing.
This solution, which is available from Phase One, consists of a 6 pin male to 4 pin adaptor and cable. Employing this adaptor and cable allows the photographer to cut the power on the FireWire bus, making the P-back battery the power source.
Several other adaptor types are available from other vendors, and may have the same effect, namely cutting power on the FireWire bus, and thereby enable the battery in the P-back to be the powering source. Please remember though that Phase One still recommends that you stay within the 4.5 meter range when shooting tethered to a computer and these other solutions might exceed this range.
Note:
The later models, the P 21, P 45 and P 30, offer battery powered shooting also while tethered, without the need for a FireWire adaptor and adaptor cable. Simply connect the digital back to the computer by a normal FireWire cable.
The digital back will automatically revert to operating on its own battery power once the FireWire cable is removed.