Powering the Phase One IQ4                                       

 In Brad Kaye, News, Phase One, Tech, XF IQ4 Blog Series

The IQ4-150 represents the highest fidelity capture of any digital back available today and within it resides the most powerful computer that Phase One has ever shoe horned into any of their digital backs.   Touted as being 10x more powerful than the IQ3 series it replaces, battery life is a concern on it like no other digital back we’ve worked with so far.

I’m not going to paint the battery life as terrible, because it isn’t, but at the time of this writing in System Firmware 6.01.1, the IQ4-150 requires some clarifications as to best-case workflows to preserve electron life in it.  Phase One is actively working on Firmware that will resolve some of the issue I’ll illustrate below.

IQ4-150 on XF Compared to IQ3-100 on XF

I set two identical cameras up and shot a use-test designed to be similar to a normal still life shoot.  3 minutes of Live view, followed by 5 minutes of shooting followed by 5 minutes of idle time, rinse & repeat.  At the end of each test cycle, I recorded the displayed battery life of the IQ digital backs, as well as the XF.  During the 5 minutes of shooting, 30 captures were made via the Time Lapse tool on XF camera body.

The IQ4-150 managed just over an hour and a half, which didn’t feel too terrible.

The IQ3-100, however, was the clear winner in this shoot out, approaching 3 hours of total time up.  (It may have made it there if I had not been asleep at the wheel 2x when I let the live view run for an extra 2 minutes on one session and 1 minute on another session)

What is immediately apparent is that the IQ4 with its current firmware package does a lousy job of sharing power with the XF compared to IQ3-100.  It was the sacrifice of the XF battery that allowed the IQ3 to continue strongly through at least an additional 5 cycles of test time.

Solution: – USB 3.0 Tether (BAD – Does Not Charge)

Well, not really.   While I was plugged into the high-power side port of my Other World Computing Thunderbolt 2 Hub, unlike the extended life of the IQ3 that could draw idle power from high-power ports of USB-3, there was zero benefit to IQ4-150.  After recharging the exact same Phase One factory batteries, each one placed back in the same location of XF body & IQ4, there was no extension of life due to the small amount of current available from that tether.  As the info window displays, while there is power on the line, none if it is available to charge the battery.  (blue dot on digital back demonstrates Live View running in the background of the info screen, hence the ~2 amp discharge from the battery)

Solution: USB-C Tether (BEST – Powers & Charges)

USB-C is a perfect tether for IQ4 as it provides a surplus of power to the digital back, not only keeping the unit fully supplied but also providing charge to the battery.  Handy if you’re on set with a wall-powered computer, not so handy when you’re tethered to a MacBook Pro, because System Firmware 6.01.1 / IQ 4.01.1 does not allow you to deselect powering from the host machine.  This will leave your laptop dead in only a few hours of location work, forcing you to plug in for the rest of the day vs just changing batteries in the digital back and remaining mobile.   (Laptop Workaround:  Use a USB-C to USB-A dongle, then use the USB-A to USB-C tether.  Not pretty, but your laptop will not bleed out)

Solution: Ethernet (POE) (GOOD – Powers IQ4)

Ethernet by itself will not deliver any input power to your IQ4, but if you have a POE injector (Power Over Ethernet) then you can work all day long with no battery changes.  If you de-tether to roam and then reconnect however, POE does not have the bandwidth to charge the battery at all, so whatever you drain to while roaming will be the state it continues at while ethernet tethered. POE Injectors require external power, so this workflow is best for studio use.  (The display in the image above suggests that the battery is being drained, but I tested 15 straight minutes of Live View with no degradation of the battery level)

Solution: XF Power Supply – XF Port (BAD – Does Not Charge)

As stated previously, the XF does not power share well with the IQ4 and given this fact, it still does not power share even when it has the 24v external power supply plugged into it.  IQ3-100 can charge both batteries with this plugged into the XF port.

Solution: XF Power Supply – IQ4 Port (BEST – Powers & Charges)

Just like USB-C, the XF Power Supply plugged directly into the IQ4 provides robust power and the ability to charge the installed battery even while running Live View.  If working with a technical camera, you will also need the Phase One BOB to share the 12-pin port with power and sync connections.

Best Location Laptop Solution:

Ethernet Tether with USB-C Power Bank (Powers & Charges IQ4 – Does not drain Laptop Battery)


Best of all worlds: Relatively unlimited tether length with inexpensive Ethernet cabling, USB-C Battery Bank with 4x capacity of a single Phase One 3400mAh battery and combined with internal battery for a total of 8.4 hours* of run time out of the IQ4. (*given the same use as the above tests) 

  • For the specifics of setting up Ethernet Tethering, please refer to my IQ4 Technical Basics page
  • I have found no luck with using USB-C to Ethernet dongles, but by using a USB-C to Thunderbolt 2 dongle and then a Thunderbolt 2 to Ethernet dongle, I get perfect connectivity
  • If your laptop goes to sleep or you have to remove the tether, a restart of Capture One is necessary to reestablish the Ethernet Tether.
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