We spent ten glorious days photographing with the Phase One XT camera system with Rodenstock HR Digaron lenses and the IQ4 back. Is this the ultimate camera for landscape and architecture? Let’s find out!
TGIFridays: Review of the Phase One XT Camera System
If you don’t already know, Phase One is the top of the top in the stills camera game. Much like Patek Philippe is to the watchmaking world. Or Arri is to video cameras. They do have competitors, but are generally regarded as the ne plus ultra of the genre. We have covered in some detail, their jack-of-all-trades do-it-all camera: the XF with the marvellous IQ4 150 digital back. The XF is a formidable camera, especially now that the closest competition is from Hasselblad, who have recently discontinued their H6D-100C. Though if we are being pedantic, the H6D-100C “only” has a resolution of only 100Mp. And while the XF equipped with the old IQ3 100 already equals this resolution, when fitted with the IQ4 150, it gets 50% more resolution plus a superior BSI sensor. And thus the XF has become the undisputed king in the studio. And the IQ4 150 is considered as the best of the best in the digital back arena. Almost silencing all competition. And here, for our consideration, we have the Phase One XT. This is Phase One’s offering in the mirrorless digital format. And one which is originally pitched as a field camera, targetting landscape and architectural photographers. Although we have had success using the XT for portraits.
Why landscape and architecture? Well these disciplines call for a considered, slow and contemplative approach to photography. This is a different genre and requires a different skill set from the sports photographer, who needs to capture the split second image. Or the street photographer, who is looking for what Cartier Bresson calls the “decisive moment”. In these disciplines, the photographer needs work quickly, almost instinctively. But in landscape and architecture, and to some extent portraiture, the photographer works meditatively. Slowly. Deliberately. The setup of the camera can take from several minutes to many tens of minutes. The consideration of the image composition and subject framing is to ensure that the camera sensor captures the image that is pre-visualised. He considers the technical aspects like exposure and takes careful measurements, before capturing the photograph.
And for this style of photography, a sturdy tripod and tripod head is essential. I have used a Gitzo GT3541S system for the better part of a decade. When I was shooting with the Panasonic Lumix GH-2, this tripod cost more than the camera itself! But it is critically important to work from a stable base. A good tripod provides that. And holding the camera to the tripod is the Photo Clam Multiflex head, also one which I have owned for more than a decade. And also costing more than the Lumix GH-2 body. The Multiflex is a goniometric device, with a precision gear driven system for all 3 axis. It is somewhat of a copy of the Arca Swiss Cube. But when I needed the head for a Grand Canyon trip in 2010, the Cube was out of stock, and the Multiflex was in stock. So I bought the Multiflex, for not much less than the cost of a Cube.
The Phase One XT Body
The Phase One XT system comprise of three elements. The XT body with with rotating back mechanism, the lens system in X-Shutter, and the digital back. The base component of the XT is the body. This is a thin slice of aluminium, machined to accept the IQ4 150 digital back on the rear, and the Rodenstock HR Digaron lenses on the front. A hand grip with a shutter release button and strap attachments are located on the right hand side of the body. The body features the ability to apply movements to the back, making this a technical camera. The movements are 12/12mm rise/fall, 12mm/12mm left/right shift. And the body measures 160mm x 148mm, weighing in at 700g. The body also features connections to allow electronic communications between the digital back and the lens. This allows the back to control the aperture and shutter without the use of additional cabling. The body also incorporates sensors to determine the position of the movements and is able to pass this information to the digital back to be recorded in the EXIF.
The IQ4 digital back is mounted on the back of the body. Also visible in the photograph below, are the two thumb wheels which control the rise/fall and left/right shifts. A gauge by the side of each wheel shows a measurement of the amount of movement applied. These movements have detents every 5mm. This operation of turning the wheels to make the movements are very smooth with a nice resistant feel. It is self locking and does not require a separate lock, even when shifted up or down with the considerable weight (about 700g) of the IQ4 back. This movement measurement is transmitted to the digital back, which can record the data on the EXIF file for use during post processing.
On the front side, Phase One has also designed into the mount mechanism a rotating system, allowing the body and back to be rotated from landscape to portrait mode. This is operated by the big clip seen just above the head clamp. Once released, the entire body plate is rotated leaving the lens un-moved.
Also visible in the photograph above is the locking mechanism for the lenses. Two latches and a safety catch secures the lens to the camera. When the lens is first connected, the safety lock will click into place and prevents the lens from falling off. The two silver tabs are then pushed to secure the lens. This works very well, with no play when the lens is mounted. To remove the lens, both latches are release via the silver tabs, and while holding the lens in one hand, the safety lock is used to release the lens.
The Phase One IQ 4 150 digital back
The brains of the system is the IQ4 150 digital back. This is currently the most advanced digital capture sensor system in the world. The CMOS BSI sensor is also the largest, measuring 53.4mm x 40.1mm and is almost as large as traditional 120 roll film 645, with a crop factor of about 0.9X.
The IQ4 150 digital back has been discussed on my review of the Phase One XF system, and remains unchanged. I have also used it extensively when I had the Alpa 12 Plus. The sensor is developed by Phase One in collaboration with Sony. The back is very sophisticated, and runs Capture One within. This allows the back to perform complicated algorithms which enables it to offer Frame Averaging, Dual Exposure and other advanced features not found on other digital sensor systems. I explored the excellent feature of Frame Averaging in my photo examples of the XF here.
When used with the Capture One raw conversion software, this is a class leading solution to professional image making. I also discussed the Capture One software in a bit more detail on the XF review. The only nitpick on the IQ4 back is that is slow to start up, and to operate, but this is the nature of this style of photography, so is not really a disadvantage. Also the back does get fairly hot (though within specifications) and consumes batteries quite fast. The loaner set came with 6 batteries, which is sufficient for a full day of shooting.
The lenses: Rodenstock HR Digaron
The final component of the XT system is the lenses. The system is built specifically around the Rodenstock HR Digaron lenses. These Rodenstock lenses offer exceptional optical performance. The optics are almost distortion free, with excellent colour and contrast rendition. And of course very sharp across the aperture range. The Rodenstock HR Digaron lenses are also fitted with the X-Shutter which is an electronically controlled leaf shutter built into the lens. The X-Shutter is designed by Phase One for aerial photography, and is manufactured by Cambo for them, incorporating this into the Rodenstock optics. The X-Shutter enables the lenses to communicate with and be controlled by the IQ4 digital back. Currently, six lenses are available, in focal lengths of 90mm, 70mm, 50mm, 40mm, 32mm and 23mm. On loan to me for this testing are 5 lenses, as I did not have access to the 40mm. Phase One also recently introduced a +/- 3° plate for the 32mm, 40mm and 50mm lenses. I also did not have access to the tilt lenses, and it is unclear if this plate can be mounted on existing lenses to provide additional tilt functionality, or the tilt lenses are standalone lenses on their own. All lenses performed at the highest levels during my tests, always providing the most superior results. Here is an interesting comparison between the Rodenstock HR Digaron-W 50mm f4 with the Fujifilm GF 50 f3.5 R LM WR.
An important consideration when looking at shift (and tilt) specifications for the camera bodies is the image circle of the lenses. This is the size of the image which is cast by the lens. Larger format lenses will have larger image circles to cover the sensor format. For the IQ4 150, currently the largest digital sensor in the market, the lenses need to cover a minimum image circle of 68mm. All six Rodenstock Digaron lenses have image circles which will sufficiently cover the entire sensor. The HR Digaron-SW 90mm f/5.6 has the largest image circle at 120mm. This means that a maximum of 33/29mm of shifted/rise/fall can be used by the IQ4 sensor. While the HR Digaron-W 70mm f/5.6 has an image circle 100mm, offering 22/19mm movement. The HR Digaron-W 50mm f/4, the HR Digaron-W 40mm f/4, and the HR Digaron-W 32mm f/4 all have image circles of 90mm and can offer a maximum of 16/13mm movement. The widest HR Digaron-S 23mm f/5.6 has an image circle of only 70mm, allowing only 2/2mm shifts.
The Phase One XT has shift/rise/fall limitations of a maximum of 12mm in either axis. Thus, except for the 23mm, all Rodenstock HR Digaron lenses have larger image circles than the XT body’s capabilities. In other words, the XT will not be able to take advantage of the entire image circle of the lenses. Except for the 23mm, which will hard vignette before the back reaches its movement limit.
Why has Phase One chosen the movement maximums at 12/12mm in both axis? In our view, this limitation is well chosen. The larger the movement ability of the body, the larger (and heavier) the body will need to be. And except for the 90mm which has a circle which is much larger than possible to cover with the XT, the other lenses will have image circles are almost fully utilised. In contrast, the Alpa 12 Plus has 20/20mm on both shift/rise/fall, and these will hard vignette when used with maximum movements on the 70mm, 50mm, 40mm and 32mm lenses (and of course the 23mm), and will only be able to take advantage of a larger movement with the 90mm. In turn, the Alpa 12 Plus is significantly larger than the XT.
Competitive landscape
This is the top of the pyramid, as camera systems go. Superb optics coupled with a best of breed digital back and an excellent body. But is it the ultimate? In the same landscape we find the usual three other competitive options.
Option one is the Alpa 12 Plus. This is perhaps the most refined camera of the bunch. The body dimensions are 184 x 184mm, weight: 1025 g. In our review of the Alpa 12 Plus, also equipped with the Phase One IQ4 150 digital back and Rodenstock HR Digaron-W 32mm f/5.6 and the Digaron-W 40mm f/4 lenses in X-Shutter, we found the Alpa body to offer a touch more precision and refinement. The controls are somewhat smoother and the build quality of the body components (the back and lens are the same!) are machined to a higher tolerance than the XT. As we noted in this comparison between the XT and 12 Plus, the XT is more industrial in its approach and the Alpa is more artisanal.
The Alpa also has the ability to use other sensors, like the Hasselblad CFV and X or Fuji GFX, which are much more competitively priced than the IQ4. However, as the X-Shutter only works with the IQ4, and when using these alternatives, the photographer is limited to use non-X-Shutter lenses, and employ either the electronic shutter on the sensor, or or a fully mechanical shutter like the Copal 0 (and other defunct electronic shutters like those made by Sinar). OK, Alpa offers the FPS as an alternative, but it is expensive, and quite cumbersome to use. For the GFX users, there is one additional option, which is to use the body’s built in focal plane shutter. The Alpa 12 Plus also offers a wider shift capability with 40mm (20/20) horizontal and 40mm (20/20) vertical, but as discussed above, this will only be useful on the Digaron-W 90mm. In counterpoint, the XT offers two additional conveniences not provided by Alpa, nor by any other competitor. Namely the ability discard the cable from the X-Shutter to the digital back as the XT body provides this connection. And the ability to change from landscape to portrait orientation without having to remove the back. This rotating back capability is not only a convenience, but ensures that the optical center of the lens remain unchanged during the format change from landscape to portrait and vice versa.
Another possible competitor candidate is the Cambo WRS 1600. The body dimensions are 180 x 160mm, weight: 920 g. It offers 40mm (20/20) horizontal shift and 40mm (20/20) vertical shift, exactly the same as for the Alpa 12 Plus. Cambo also manufactures the Phase One XT body and the X-Shutter, though the designs are by Phase One. And the system is capable of using the same Rodenstock lenses. The Cambo has the added flexibility of being to take advantage of Hasselblad (CFV backs as well as X bodies), the Fuji GFX as sensors with some limitations, as noted above. The Cambo, like the Alpa will require an additional cable from the X-Shutter to the IQ4 back, will not have a rotating back and will not record any positional movements to the EXIF.
Arca Swiss offers the RM3Dii is the third consideration. The body dimensions are 195 x 200mm, weight: 1050 gr. The Arca Swiss takes a different approach with their 40mm (30/10) asymmetrical rise/fall on the vertical and 30 mm (15/15) horizontal shift. But with the Digaron lenses, this large movement maximum is mostly moot due to image circle limitations discussed. And the same advantages of being able to use different digital backs is applicable. As are the disadvantages of requiring a cable, no rotating back and not having access to EXIF positional data applies.
Sample photographs, next week!
OK, this has turned out to be longer than I had originally anticipated. So I will leave the sample photographs made with the Phase One XT system, and my concluding thoughts for next week.
