The Phase One IQ4 150 XF Camera System

The IQ4-150 represents a technological leap forward in the IQ digital back series, now using a Linux based operating system, the mini-computer backing the BSI 151mp sensor is 10x as powerful as the hardware running the proprietary operating system in the IQ1, IQ2 and IQ3 digital backs.  The User Interface is completely new, so you will have near zero muscle memory for the basic operation of this unit, and many of the features and tools present in the current firmware of the IQ1/2/3 series digital backs have not yet made it into the ever developing firmware of the IQ4-150.

This article represents a distillation of meaningful items from the XF / IQ4 User Manual, client responses to using the gear, the information I currently know from personally working with the IQ4-150 since about November of last year.    While I’ve worked extensively with a number of digital backs that I’ve tested and certified prior to client delivery, I’ve only recently had the chance to shoot the unit on a commercial job, in which it performed perfectly, albeit with the workflow issues that will be illuminated in the following text, videos and images.  This article will evolve and update as we receive new firmware and new discoveries are made.   -BK

Preparations for your IQ4-150 Delivery

XF Firmware:

To use your IQ4-150 with your XF, the camera will have to be updated from its current 4.01.5 firmware to a version compliant with the IQ4-150.  Currently 4.02.13, this can be loaded via the combined firmware updater for IQ4-150, 1.00.18. (Swipe Up, Select Menu-List, Scroll Down to System Settings–> Firmware–> Update Firmware)


If you want to ready the XF camera ahead of having the IQ4 available, you can download firmware for XF 4.02.13 below, place it on your CF card and update using your IQ1/2/3 series to perform the update. (Menu–> XF Menu –> Update Firmware)


Capture One minimum supported Versions
IQ4-150: 11.2    IQ4-150 Achromatic: 12.0.1 


IQ4 150 / XF Firmware Downloads

IQ4-150 1.01.18
IQ4-150 1.00.2
Note, this is still technically a beta firmware for the XF body and does not provide full feature use of the XF if attached to a IQ1/2/3-series digital back. (At least one instance of this incompatibility manifests if exposures 1 second or longer are shot while using vibration delay which produces an endless post-capture count up that will disallow the file to be written)  We expect a single firmware package in the future, but for the time being the valid versions are:


XF Firmware for IQ1/2/3 4.01.5                 XF Firmware for IQ4-150 4.02.13


LongPress on Lower Left button for IQ Menu


Not that firmware updating was ever inconsequential in the past, but realize that with the IQ4 we’re talking about a much more robust computer packed into the same form factor as the prior IQ backs, containing much more programming complexity.  The firmware package that updates the unit is 12x larger than its predecessors and the update process is no less impactful than an operating system update on a desktop computer.  Make sure you start any firmware update with a completely charged battery and wait, even through what seem to be long periods of black screen time for the update to finish with a confirmation screen.


New User Interface and Workflow:

IQ4 Home Screen

As previously stated, there is very little similar between the way you work with all IQ-series digital backs up until now, and the IQ4.


LongPress on Lower Left button for IQ Menu

A long press on the lower left hard button brings in the swipe up menu structure with the right side buttons acting as scroll.  Missing, however, is the ability for gloved hands to change any of the shoot parameters like white balance or file format without at least a nose-tap confirmation on the screen itself.

OPINION:  While the swiping behavior is a desirable leap forward in navigation, it’s a bit overly active in the corners, sometimes activating when you’re trying to make a push selection of an item, or somewhat maddeningly when you’ve already made it into the deep menu structure and are scrolling up and you swipe in the Menu System again.  I have filed a feature request to deaden the corners of the display for the swipe behavior. 

Live View

One of the most significant changes to user workflow is that Live View now simulates exposure based on the camera settings.   This means if you’re setting up for your dawn exposure, you’re going to have to crank up the ISO in order to see your frame in Live View, and then lower the ISO back down when it’s time to capture.


WORKFLOW TIP: When connected to the XF, this is easily managed by the default behavior of the rear wheel on the camera.  Rotate right (counter-clockwise) to spool the ISO up until you can clearly see your frame.

Focus peaking is turned on by default and the mask will display in a tethered Capture One session as well.  To turn off Focus Peaking, swipe in from the right to and toggle the eyeball icon.  A long press on this icon will allow you to modify the Focus Peaking Threshold

Currently, there is no invisible zoom slider on the left margin like prior IQ Live View screens / Image navigation, nor is there a zoom increment displayed.  


VERY IMPORTANT NOTE on Live View and Long Exposures

The IQ4 Live View frame rate runs essentially at the shutter speed selected, so when your exposure is set to 1/8th, you can expect somewhere around 8 frames per second of refresh rate, compared to the ~55fps the digital back is capable of displaying in Live View.

!!  Exposure times beyond 1 second will not produce a Live View image  !!

ISO gain is absolutely necessary to see any image at all if your operating exposure is longer than 1 second so you’ll need to add ISO and then speed up your shutter speed to see your frame.  (remember to drop your ISO back down and re-adjust your shutter speed before taking your shot, oh boy do we need the Exposure Calculator tool back in the interface!) 

(Phase One plans to add the yet to be officially named, IQ1/2/3 Live View behavior with auto ISO gain back into the IQ4 in a future firmware release.)

Boot Up Time

At ~18 seconds, the time to see the home screen of the IQ4-150 is considerably longer than on the IQ3 series digital backs at around 6 seconds, but with a 64GB XQD card installed it is just 4 seconds slower than the ready to shoot state of the IQ3-100 with a 64GB CF card installed, so with a 128GB XQD card installed, the ready times are about matched and with a 256GB installed, it easily surpasses the ready speed of the IQ3-100 with 256GB CF card installed.

File Format Options

Now up to 5 different versions, the default on the back in firmware 1.01.18 is actually S14 which is the 2nd lowest quality on the digital back.  ‘Low’ quality is a bit of a misnomer, given the fidelity of Phase One’s even most aggressive file compression format, but you’ll likely want to bump it back up to the high fidelity standard L16.  The one below that is ‘Sensor Plus’ which shoots a 37.7 megapixel file at 1/4 resolution (7100px x 5324px). The top resolution L16-EX should only be shot at base ISO, because at any other ISO gain, there is no quality advantage to this format and requires more time from shot to shot than the other formats.

IIQ 16 Large A completely lossless compression format that saves the full 16- bit signal from the CMOS sensor. It offers excellent image quality when you want to take full advantage of the dynamic range of the sensor.

IIQ 16 Extended This format is an enhanced version of IIQ 16 Large as it provides an even lower base noise. It offers the very best in image quality when you need to extract extra detail in the shadows.

IIQ 14 Large Saves a 14-bit version of the RAW file using a completely lossless compression. It provides a smaller file size and faster capture rate compared to IIQ 16 Large and strikes a good balance between high image quality and size.

IIQ 14 Smart Is an intelligently compressed RAW file format, which strikes an excellent balance between file size and image quality. It can be used in almost all applications as the “Smart” compression is so efficient that it can be difficult to notice any difference over the IIQ 14 Large. However, since there is a very small loss of data, Phase One does not claim that IIQ 14 Smart is completely lossless, but what they call “near lossless”.

IIQ 14 Sensor+ This Sensor+ RAW format is the perfect solution when you need a lower resolution file but still want to retain all the advantages of the RAW file. When selected, the Sensor+ RAW file will be exactly a fourth of the normal 151-megapixel resolution, giving you a 37.7-megapixel file. You will maintain the advantages of the RAW format, like being able to adjust white balance.

IQ4-150 Shoot Speeds per format, Frames Per Second

L16-EX  .7 fps  |  L16 1.1 fps  |  L14 1.3 fps  |  S14 1.3 fps  |  S+ 1.3 fps

Capture One Inside IQ Styles

The IQ4 ships with six IQ Styles that each are optimized for specific image subjects or workflows.

1. Landscape aims to provide detailed landscape images in scenes with a high dynamic range. The style boosts saturation slightly as well as recovering detail in the highlights and shadows. Finally, midtones are warmed slightly.

2. Fashion is optimized to ensure that you can evaluate that skin tones are neutral and smooth. Contrast is increased to add some pop to the image while saturation is reduced. In addition, the color balance applies a cold/warm split to the shadows and midtones.

3. Still Life provides an attractive alternative to the typical captures in Studio photography. The style applies a crisp contrast increase while lifting the brightness of the image without effecting saturation.

4. B&W Neutral replaces the “Black and White” view mode found in previous IQ digital backs. The effect basically mirrors enabling Black & White in Capture One.

5. B&W Contrast is a Black and White conversion style with some added contrast that makes the images pop more than B&W Neutral.

6. IQ Professor The Image Quality Professor’s choice of image adjustments. Please see the Image Quality Professor’s blog on for an explanation of the included image adjustments as this style is meant to showcase the possibilities of the IQ Styles and might change with a future firmware.

Internal File Writing

New to IQ4 is the XQD card which supports rates up to 440 mb/s write speeds, nicely in excess of the ~220 mb/s needed when the camera is being fired at full speed.


In-camera redundant archiving is now also available to the SD slot, with card speeds currently available up to 300 mb/s.


Default mode for the SD card slot is disabled, but can be selected for mirrored JPG files, or ‘Archive’ for IIQ redundancy through the SD Storage menu option.  (Triple redundancy is available if tethered by USB-C, Ethernet or WiFi)


The XQD card is inserted with the write-speeds facing away from you, the SD card is inserted with the write-speeds facing you.  The edge of these cards can camouflage themselves into the digital back as well as the card reader, so keep an eye on them so you don’t leave for a shoot with it still mounted to your computer.


Card Writing Speeds (fastest currently available):
XQD: 440 mb/s  available in 32, 64, 120, 240, 256 GB Capacities
SD: 300 mb/s  available in 32, 64, 128 GB Capacities


Formatting the memory cards

You can format the XQD or SD cards independently. Just go to the IQ4 menu and select Storage Setup –> Format XQD -or- Storage Setup > Format SD.
A warning is displayed as a safety measure, so just tap on OK.

Tethering Options


New to the IQ4 is the first IQ-series digital back to break from the Firewire 800 pushing into your chin, and instead, offering Ethernet & WiFi tethering as alternatives to the native USB-C port on the side of the body.   Each have their benefits and drawbacks.


USB-C:  Very fast, but cable lengths are limited to 15′ and at even that length, there is no power distribution from your computer to the battery of the IQ4.  USB-C to USB-C and USB-A to USB-C tethers are available.


Ethernet*:  At this moment, speeds have been testing at ~ 12 MB/s.  Power Over Ethernet (PoE) will be an option in a future firmware release.

WiFi*: WiFi tethering isn’t going to break any speed records, but is a very handy way of transferring shoot images to your computer.  Hugely variable transfer rates, even with a dedicated router 2MB/s – 5 MB/s, mostly staying around  2.5 to 3 MB/s

*WiFi and Ethernet tethering require connection to a router, preferably a dedicated unit, in order to connect to Capture One.   Establishing a connection isn’t as simple as the immediate recognition of the digital back when using the USB tether.

If you’re playing around with the different tethering sources, Capture One will have to be restarted between using Ethernet and Wifi. 

File Buffer:  You can shoot a burst of about 11 images in IIQ-L16 or 22 images in IIQ-S14 before the internal buffer fills up for ether Wifi or Ethernet tethering, then just like burst shooting of old, you must wait until the unit clears a shot to take a shot.
–Coming Soon–
Hähnel Pro 2 Cube Charger interface explained

Technical Camera Use


At this moment, the IQ4-150 is limited to its internal electronic shutter only, as no external cable is yet available between the 12-pin side port and technical camera lens or shutter system (a cable solution is shipping soon).  When disconnected from the XF body, Electronic Shutter must be first turned on in the Camera menu (swipe up, top selection).  The Hähnel electronic cable release for the XF camera or Phase One’s BOB can be used in the 12-pin side port to fire Electronic Shutter w/o touching the digital back.  (No delay timer is yet available on the User Interface) 

Features Missing from IQ3 in IQ4 Firmware 1.01.18

Promised, but not yet delivered, these features from IQ3 have not yet made it to the IQ4 series digital backs.

• Exposure Calculator
• Post Capture Zone Display
• Post Capture Focus Mask
• Calibration for Horizon Level
• Custom Splash / Lock Screen
• AdHoc WiFi communication
• Adhoc WiFi communication with Capture Pilot
• Zero Latency for Technical Camera
• XF System Information (frame counts/serials of lenses)
• Countdown Timer for long ES exposures on Tech Cam
• ES Delay Timer
• Shoot Directly to USB-C hard drive
• Frame Averaging
• ‘Viewfinder Mode’ for Live View
• XF Power Sharing
• Post Capture Vertical display of Vertical images

Current Bugs in Firmware 1.01.18


• XF Firmware 4.02.13 NOT compliant with IQ1/2/3 DB’s
• XF ‘Screen Sleep’ setting is not being observed.  Camera goes dark (and camera goes to sleep) somewhere less than 5 minutes, even if set to ‘never’.
• With ES enabled on XF body: (firmware 1.00.2 / 1.01.18)
 – EXIF data does not report focal length (of zooms)
 – HDR changes exposure, but only reports middle exposure value on each file in that set
 – No indication nor frame count of multi-exposure grouping (time lapse, HDR etc)
• If working exclusively through Capture One control of the unit on Technical Camera, the untouched unit will warn of its impending power-saving shut down, even after just completing an exposure.
• Battery Information is not conveyed through the tether to Capture One
• Live View image artifacting while zooming/panning when using shutter speeds longer than 1/2 second
• Live View image artifacting while zooming into specifically the far right side of the frame
• When disconnected from XF, IQ4 will still show shutter speed unless Menu–> Camera –> Electronic Shutter is toggled ‘on’ and then back off.  Displayed value is irrelevant.
• SD ‘Archive’ mode will variably not write files to SD card (Images will hold as ‘pending’ in the status menu, primary writing is unaffected)


The much anticipated ‘Frame Averaging’ feature is simply not present in the firmware as of this moment.


A valuable tool for proper troubleshooting is the Dump Log.  If you encounter problems not already listed here, with the XQD card installed in the digital back, please gather a dump log and send it over.
After downloading the file to your computer, please append your name to the beginning of the file, (DustyTanglewood_Log003.bin) before emailing it.