Phase One IQ4-150 Technical Basics

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, and the information I currently know from personally working with the IQ4-150 since November of 2018.   I’ve worked extensively with dozens of digital backs that I’ve tested and certified prior to client delivery as well as shooting terabytes of images through these units on commercial jobs, 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 (January, 2019)

** VERY IMPORTANT Preparations for your IQ4-150 Delivery **

XF Firmware:

To use your IQ4-150 with your XF, the camera will have to be running at least 4.05.3 firmware to be compliant with the IQ4-150 and be seen by the digital backFailure to update to this firmware prior to trading in your existing digital back will unfortunately leave you with two objects that have no common language to communicate with each other.

Please ready the XF camera ahead of receiving your IQ4 by downloading firmware for XF 5.00.5 or 4.06.3 in the Firmware Updating section further below, place it on your CF card and update using your IQ1/2/3 series to perform the update. (Menu–> XF Menu –> Update Firmware)[This firmware package is to be used only in an IQ1/2/3-series digital back]

Capture One minimum supported VersionsIQ4-150: 11.2    IQ4-150 Achromatic: 12.0.1 

Important Note!  Capture One Preferences MUST be set to IIQ format NOT TIF for the raw file to be editable in the program.

IQ4 Technical Basics – New User Interface & Workflow

IQ4 Home Screen

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.

Live View

One of the most significant changes to user workflow is that by default 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 want to swipe in from the left and bring in the new ‘Viewfinder’ mode which adds auto ISO gain, and if necessary, reduced frame-rate to Live View so you can once again, easily use the view shown on the digital back for composition purposes.

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.

Firmware Updating

Based on the build date (or date of last service) of your IQ4 it will have a ‘Factory’ firmware installed on it from that period of time. Depending on the version of this factory firmware, you will need to step up incrementally if you haven’t been adopting the new firmware as it originally deployed.

All firmware installed after 4.02.7 requires that you have had already installed XF System 4.02.7 prior to using that next version (5.x / 6.x etc.) update. All firmware installed after 7.00.7 requires that you have had already installed XF System 7.00.7 prior to using the newest (currently 8.03.2) update.

Example: If your IQ4 was running XF System 1.03.25 firmware and you want to bring it up to current, you would need to first install 4.02.7, then 7.00.7 and then finally 8.03.2

Somewhat confusingly, the XF System Package acts as a container for the specific XF & IQ4 firmware versions.

  • XF System 1.01.18 installs XF Firmware 4.02.13 and IQ4 Firmware 1.01.18 (First Release IQ4 Firmware 1/17/19)
  • XF System 1.03.25 installs XF Firmware 4.04.9 and IQ4 Firmware 1.03.25 (3/13/19)
  • XF System 4.02.7 installs XF Firmware 4.05.3 and IQ4 Firmware 2.00.20 (5/24/19) (Installation REQUIRED before upgrading to System 5)
  • XF System 5.00.20 installs XF Firmware 4.05.3 and IQ4 Firmware 3.00.20 (6/27/19)
  • XF System 5.01.0 installs XF Firmware 4.05.3 and IQ4 Firmware 3.02.0 (7/24/19)
  • XF System 6.00.52 installs XF Firmware 4.06.3 and IQ4 Firmware 4.00.58 (XT release, broken for Tech Cam & XF shooters 9/25/19)
  • XF System 6.01.1 installs XF Firmware 4.06.3 and IQ4 Firmware 4.01.1 (All Camera Compatibility 10/10/19)
  • XF System 7.00.7 installs XF Firmware 4.06.3 and IQ4 Firmware 5.00.13 (Installation REQUIRED before upgrading to System 8)
  • XF System 8.00.18 installs XF Firmware 5.00.5, X-Shutter Firmware 1.01.6 and IQ4 Firmware 6.00.36 
  • XF System 8.01.0 installs XF Firmware 5.00.5, X-Shutter Firmware 1.01.6 and IQ4 Firmware 6.01.3
  • XF System 8.02.0 installs XF Firmware 5.00.5, X-Shutter Firmware 1.01.6 and IQ4 Firmware 6.03.18
  • XF System 8.03.2 installs XF Firmware 5.00.5, X-Shutter Firmware 1.01.6 and IQ4 Firmware 6.04.2

Check your Firmware Version on your IQ4-150 to see if need to update prior to downloading any updaters! 
Download IQ4 150 / XF Firmware Downloads from Capture Integration

Variable BUG NOTICE for XF Firmware 5.00.5 It’s likely that you’ll upgrade your XF to this new firmware and experience the positive benefits of reduced shutter latency with no ill effects, but we’re tracking some variability when it comes to specific combinations of camera bodies and lenses that can cause lens errors and subsequent inability to capture.

If failure happens, it is because of specific issues caused by the reduced latency and increased voltage of the new programming and it could be because of a specific lens or a specific XF body not performing to the ask created by the firmware. For this reason, I would recommend keeping 4.06.3 on a card stored in your kit, in case you experience lens errors and need to revert to the ‘safer for all seasons’ tried and true 4.06.3. A camera camera that is performing fine at room temperature could potentially still have issues in extreme heat or cold as a result of these variables.

No stand-alone version of XF Firmware 4.06.3 exists for IQ4, so you will need to use the 7.00.7 system to regress the XF to the earlier firmware package. For basic testing, older firmware on both XF and IQ4 is fine, but if it works out better that the XF stays on the older firmware, this is the procedure to regress the XF but keep the IQ4 up at the newest firmware.

  • Install System Package 7.00.7 along with the newest System Package on your media card at the same time.
  • Insert into the IQ4 and ‘Update’ the camera and digital back to 7.00.7. The XF will now be running 4.06.3
  • Detach the IQ4 from the XF (place protective plates on both) and run apply to the newest firmware update. The IQ4 will now be at current
  • Re-attach IQ4 to the XF. The XF will be running tested, tried and true 4.06.3 and the IQ4 will be at the current firmware revision.

Pro Note for Firmware Upgrades:

The SAME rules of engagement apply here as I always recommend… Are you going out to shoot a job this week, with client, without internet access? Consider not jumping into any new firmware update until you have the time just to sit with your system, play, explore and notice if anything has run amok.

*** This Firmware Update will drop down to a totally BLACK screen for a period of time, please be patient and allow it to complete!! ***

Latent bugs can always reveal themselves when combined with individual workflows and patterns unforeseen by the engineering team in Denmark or bound to very specific groupings of serial #’s and build dates. I think it’s very good practice to keep prior versions of firmware on a SD card in your kit at all times. If you find that you’re having an issue with your camera, you can revert to a previous firmware package instead of the current one.

In fact, I recommend keeping several versions of firmware on that same card in order to determine whether a bad behavior is bound to a firmware release or is potentially a newly developed hardware issue. Unlike prior IQ1, IQ2 and IQ3-series digital backs, the IQ4 platform can see and access more than one version of firmware stored on the card, so it’s easy to keep those versions with you all the time.

Best to keep at least these three on your ’emergency’ SD card:

(Note: If the Factory Firmware on your IQ4 is anything prior to 8.01.0, DO NOT store your emergency firmware on a CFexpress card, as the unit running firmware prior to 8.01.0 will not even see a CFexpress card!!)

Feature Update #4 SR2

Feature Update #7 Phase One Lab & Dual Exposure+ 

Feature Update #8 

In case of the rare need to perform a Full Reset on the IQ4, having the necessary versions of firmware to build back to the current version will be valuable to get you back to shooting with all available features. If this need arises for that ‘2-button reset’, the IQ4 will revert to whatever firmware version was current at the time it was produced or last serviced. If you have an early build, this could mean needing all three packages above.

Current and Prior versions of Firmware available in our Download Archive


At Phase One: Firmware for the Phase One XF & XT Camera Systems

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 up to 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.

Creative Control Package

Automated Frame Averaging

The Automated Frame Averaging feature will merge multiple captures into a single IIQ RAW file, averaging the exposure value automatically. The benefits are two-fold; you can achieve a long exposure look without having to use a Neutral Density filter, which may introduce color cast or other image quality issues. The nature of the feature also means that any random captured noise will be neutralized, resulting in superior image quality. Automated Frame Averaging is enabled from Camera Controls by sliding your finger in from the right and tapping on the icon.  For more information see: Phase One IQ4 – Long Awaited Frame Averaging

Custom IQ Styles

Capture One Inside now enables photographers to load their own custom styles into the IQ4, so that the captured images can reflect your own unique vision and style. The Custom IQ Style can easily be created in Capture One Pro and saved to the memory card, imported into the IQ4 and used as a unique look on the next captures. In addition, Capture One Inside now supports the Clarity and HDR image adjustments.

Workflow and Storage Flexibility

The Direct Image Transfer feature will automatically copy the RAW files on the XQD and SD cards from the IQ4 to the connected computer via Capture One. This is can be very convenient as you don’t need a card reader to transfer the files. Storage on the SD card can now be combined with the XQD card in four different ways to ensure that you can always choose the optimal workflow. There are two new SD card features. Primary Storage ensures that you can capture the RAW files directly to the SD card without the use of a XQD card, while the SD Overflow feature combines the XQD and the SD memory cards as one, single storage unit for RAW files, where the images will automatically and seamlessly be saved on the SD card once the XQD card is full. The new features are accessed from the Storage Setup menu.

Exposure Zone tool on the IQ4

The Exposure Zone tool is added on the IQ4 and displays a visualization of the exposure range of the captured image based on the raw luminosity data. It is useful in determining the absolute point at which highlights will clip. The Exposure Zone tool is found in both the Viewer and the Tools Viewer by changing the masks Mode setting.

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

Black Frame Reference

For the first time in the history of Phase One digital backs, the IQ4 can operate without even a single Black Frame Reference being recorded at the time of capture.  It does this by referring to an internal LUT that based on temperature, length of exposure, ISO etc, applies an appropriate noise reduction algorithm.  The benefit, of course, is that in the example of a 1 minute exposure, a 1 minute Black Frame Reference does not have to be captured, delaying your ability to fire the next frame.

The caveat to this, is that any hot pixels that the sensor array produces are not automatically removed. Every digital back available to us in the consumer market has been and is going to produce hot pixels, we just never saw them before because Phase never allowed us to, because in combination with the mandatory Black Frame Reference they were removed within Capture One behind the scenes. The only people on the planet that get perfect digital sensors are organizations like NASA and they come at the cost of $Millions, so if we capture without the Black Frame Reference, we have to deal with a number of bright pink/white pixels that will manifest on the shot, often appearing in the darkest areas of the shot.

To avoid these hot pixels, you have two workflow solutions available:

• Toggle Black Ref to Create rather than Prerecorded in Menu—>File Settings—>Black Ref on the IQ4. (with the necessary result that any exposure time will be met with an equal time for black reference before the next capture can be made, just the same as prior Phase One DB workflow)

• Use the Single Pixel slider in the Noise Reduction tool in Capture One to remove those hot pixels when Black Ref is set to Prerecorded.   Even a value as low as ‘1’ in that tool removes many of the errant spots.

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

ProGrade cards are recommended, Sony ‘Tough’ Cards are Not Recommended by Phase One for use in IQ4’s

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.  Even newer is compatibility with CFexpress (CFX) cards touting 1700 mb/s. (Note: Capture One will not automatically launch the importer for CFexpress cards but if they’ve been formatted in the DB and carry the same ‘PHASEONE’ name, the importer will likely see it immediately when you launch it)

To be clear, the 400 MB/s write speed of XQD cards is not a bottleneck for shoot speed for the IQ4-series digital backs but the 4x+ read speed rating will improve download speeds to your computer, although different card readers through different computer ports perform wildly differently. (See Phase One Feature Update #8 – Tested Features, Procedures & Caveats for more details)

Default mode for the SD card slot is disabled, but can be selected for:

  • JPG for mirrored JPG files with active Capture One style applied,
  • Archive for IIQ redundancy,
  • Primary Storage to enable writing to SD only, or
  • Overflow which makes the SD the overflow destination once the XQD card has been filled.

All these options are available through the SD Storage menu option. Triple data redundancy is available if tethered by USB-C, Ethernet or WiFi as well as having both cards installed and Archive Selected.  (Note: If Overflow is selected, frames available will not currently display total frames available between the two cards, just the XQD card.)

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 CapacitiesSD: 300 mb/s  available in 32, 64, 128 GB Capacities

When Archive mode is selected for SD card use, images manually deleted from the XQD card are not deleted from the SD card, but remain as a viable redundant backup against XQD loss/failure or user error.  

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:  Very consistent, positive connections, no data bottlenecks, unlimited cable distance and with a Power Over Ethernet (POE) injector, no battery changes necessary. (careful, positive connections mean the camera could be yanked and the cable won’t break away)

Ethernet setup is (can be) a bit more finicky the first time and usually requires some system preference changes in the computer interface as well as some re-starts for both the digital back and Capture One the very first time you attempt Ethernet Tethering.  For the first time, go ahead and just plug it all up and see if you can select your IQ4 as ‘Camera’ within Capture One where you will see your IQ4 identified by serial number. If not, quit Capture One, and the setup basically goes like this:

1) Plug the IQ4-150 into the Cat5e / Cat6e ethernet cable and plug cable directly into ethernet port of computer or attached hub. (standard, not crossover cable)

2) Check your Network configuration in your Mac System Preferences

3) If you don’t see the ethernet port show up, you’ll need to add it manually

3) If you don’t see the ethernet port show up, you’ll need to add it manually

(For ease of physical connection, I’m using the Ethernet port on my OWC Thunderbolt hub)

4) (optional) Rename the item

5) IMPORTANT: Set the item to the top of the service order

6) No green dots here, orange is the best you’re going to get, but if you get it, you’ve got success.

7) Launch Capture One, and as with router-based ethernet tethering, ‘Add Camera’ and use the address displayed on the IQ4 swipe-down Status screen. (do not use the address in the Apple network panel)

If the tether is removed or lost of any reason, one or even two restarts of Capture One may be necessary to re-connect the unit.  Simply select the already known camera from the drop down menu within the Camera Tool in Capture One.

Power Over Ethernet (PoE) is available, but not likely from that router you’re plugged into, nor from your computer itself.  In order for PoE to work, you need a network switch providing that power.  If your ethernet environment isn’t serious enough to need a switch, (and most aren’t) you can provide power to the wire by using an PoE Injector.  This small, simple and inexpensive passthrough device will add 15 watts of power to the line, more than enough to satisfy the ~7 watt idle needs of the IQ4 and keep you shooting all day long on the same battery. (Always, always, ALWAYS plug any device that’s connected to anything to do with your system through a solid surge protector or UPS)

Ad-Hoc Wifi

A router is NO LONGER NECESSARY to connect your IQ4 to your computer and wirelessly transmit raw images to it.    Complete remote control of the camera body is possible including most all digital back and camera settings through Capture One. Note: Adhoc Wifi (Access Point) will use only the available 2.4Ghz frequencies.

Even though the Phase One IIQ compression algorithm is amazing at saving image breath and detail in a lossless, yet petite fashion, you’re not going to set the world on fire with the speed of your raw image transfers of 150 megapixel files to your computer. If your expectations set so that you expect each image to take just about 90 seconds to reach the computer, then you will enjoy the use of this feature.

If you want to raise the number of shots that travel through the air per minute, you can certainly alter the IIQ compression level to do so. Details on the 5 available IIQ formats for IQ4-150 here–, or previously in this article.

WiFi Tethering Shooting Stats: (specific computer, distance to camera and competing wifi pollution factor greatly as variables)

  • Buffer = 8 Frames IIQ-L 16-bit
  • 27’ from Computer 1.8-2.2 MB/s  
  • 6’ from Computer 2.8-6.2 MB/s  (mostly ~3.3) 

When I’m shooting interior architecture, I loathe having a physical tether between me and my computer and having to move the camera/computer pair endlessly throughout the day. Most of the time this means I’m shooting to card and then downloading the scene onto my machine that’s usually set up in an area more common to the entire shoot. Ad-Hoc Wifi will solve this problem perfectly for me, as the shoot pace of my scene that is neither breathing nor spoiling, doesn’t need dozens of frames shot especially if I’m light painting with the ALPA Silex.

Forget about using Live View if shot files are in transit, it can be about as responsive as CCD Live View with around 1fps, which makes it difficult to focus by, but otherwise works quite well when the buffer is clear of images. 

Note: If camera becomes disconnected from WiFi due to sleep or too great of distance, C1 will have to be restarted to regain camera connection.

Steps to connect to IQ4 from Capture One via AdHoc Wifi:

Battery Life

The IQ4 certainly runs hotter than prior generation digital backs, but that is to be expected given the 10x processing power built into it and you’ll notice this in handling the unit.  Typical idle temperature tends to be about 3ºC hotter than an IQ3-100 at about 33ºC (91.4ºF) and a 3-minute Live View burn will add about 9ºC to that number, where a IQ3-100 adds only 7ºC.   IQ4 Live View runs a frame rate that is more than double the speed and with considerably higher quality than the IQ3, so the 2º penalty really isn’t that bad. 
That being said, you will certainly experience shorter battery life than the IQ3, but this isn’t a horrible concession to workflow, especially once XF power sharing is restored in future firmware release.  I tested IQ4 vs IQ3 battery life and the IQ4 provided 1.5 hours of mixed use before a low-battery warning, and I was able to shoot 158 images while engaging Live View in 2 and 3 minute increments for a total of 15 minutes.   At the conclusion of this test, the IQ3 still had 40% battery remaining.

External Power

  • XF Power Supply:  As of firmware version 1.03.26, XF Power Sharing has been made available, and the XF Power Supply can plug in to provide power to the XF camera body only, or if plugged into the IQ4, can power only the IQ4. (including System 8.01.0 Firmware)
  • USB-C Tether:  If you’re tethered via USB-C to USB-C, the IQ4 will auto negotiate power from the host computer, which is certainly additive to battery life.   Whether the system stays up 100% or there is mild to moderate battery drain is entirely dependent on the host machine.
  • USB-C Power Supply or Battery: Also available is to simply plug your MacBook Pro USB-C power adapter directly into the IQ4, consuming the tether port, but providing battery charging to the unit.  This is a good option if running an Ethernet tether without Power over Ethernet (PoE)
  • Power over Ethernet (PoE): As covered previously, PoE is available with the right support equipment and will also provide all-day power to the unit.

For more on Powering the IQ4, see THIS article

Technical Camera Use

The IQ4-150 can shoot with Copal shutters, Electro-magnetical shutters like Rodenstock e-Shutter 250 with external control units like Sinar eControl or ALPA Silex, or with it’s internal Electronic Shutter (ES)
Currently, there is no ‘zero latency’ option on the IQ4, so the digital back needs to be woken up prior to the capture sequence.   If firing by traditional Copal shutter and the single-piece 12-pin to PC sync cable, tap the ‘Capture Button’ on the unit, and then within 10 seconds, fire the mechanical shutter.

Alternatively, if you have a 2-piece cable, you can use the wakeup button on the cable.

Default for the digital back is external triggering from the mechanical shutter, so if ES is desired it must first be selected.  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, in addition to the digital countdown timer in the interface.(For long exposures, there is currently no countdown for time remaining in the exposure) 
(The f-stop metadata will automatically report the last focal length to be entered or, if last attached to the XF camera, whatever it shot at last.)

OPINION: I would want to keep an eye on this data field as I would rather the camera report no value into metadata than the wrong value into metadata.  Might be a little OCD, but I wouldn’t want to shoot a project on a Rodenstock 90HR and have an impossible f2.8 burned into the metadata of the raw files   -BK


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.