The new back

The form factor of the IQ3 100MP back is much the same as the IQ250 that I tested with the 645DF+, but now offers HDMI as well as USB 3 for tethering the rig to a PC. Phase One doesn’t declare that the back can record video, but with the back tethered to a TV or monitor it can stream video, and tethered to an external video recorder the video can be recorded.

The biggest changes are inside, of course.

Key new features Phase One IQ3 100MP:

  • 100MP resolution
  • 15 stops of dynamic range
  • ISO 50-12,800
  • Better integration with body
  • Redesigned pixels that collect more light
  • Separate battery from body – but can power share
  • Exposure value display
  • Dual-value clipping display
  • USB 3 and HDMI ports

The resolution is always going to be the headline grabber, but Lau Nørgaard tells me that the pixels are a different design to those used in the previous 50MP back. He said that the diodes are closer to the surface of the sensor, which allows them to collect more light and to record colors more accurately towards the edges of the frame. The new design allows the lowest ISO setting to drop to 50 while the upper limit is extended to 12,800 – the IQ250 had a range of 100-6400. Phase One quotes a dynamic range of 15 stops.

The new sensor is also larger than the previous 50MP chip, and at 5.37 x 4.04cm it qualifies as full-frame for the 645 format (remembering that the image area of a 645 film negative is smaller than 6 x 4.5cm) so no conversion factor is required for the lenses. Recorded images measure 11,608 x 8708 pixels, which print to 38.7 x 29" if you size them to 300ppi, and weigh-in at between 100-120MB each.

The back has its own battery, as before, but now it can power-share with the body should one or the other run low. In untethered shooting battery life is quite reasonable, but when the back is streaming content to the computer you really want to use the power adapter as the batteries don’t last more than a couple of hours. I found I needed four batteries between back and body for an afternoon’s untethered shooting.

One of the key improvements in the IQ3 backs is the much better integration with the body that allows so many of the body controls to be adjusted from the rear screen. The back can adopt the display of the top plate LCD and allow touch controls, while new viewing modes allow us to see images as a color-coded exposure map, a focus map and with two degrees of clipping warning – showing what is close to being lost as well as what is lost.

This last point is one worth bearing in mind. Usually cameras show clipping warnings according to the information in the preview JPEG file, and often we find that what was flashing red can be recovered from the raw file. Phase One's system has that same red warning for the same level of clipping, that can also be recovered, but the further warning, in flashing magenta, lets us know when the highlight won't be drawn back even in the raw file. This makes judging how bright an exposure your raw file can tolerate before clipping desired tones much easier, allowing you to better expose high dynamic range scenes. This system judges what tones will be recorded independent of the white balance and contrast settings we are using, and is thus far more useful and accurate. It would be great to see similar features from other camera brands given the popularity of shooting in raw.


The camera is at its best when used on a tripod, but hand holding is possible so long as you don’t try to use shutter speeds longer than 1/125sec (to be on the safe side, stick to 1/250sec or shorter). The AF system is better than before, but still primitive compared to the multi-point systems in 35mm-type DSLRs. We have a single AF area in the middle of the frame, and while the system is quick enough in good light, it fails in low light. The best way to focus is with the camera in live view and tethered to a laptop, so you can magnify the view and get the focus exactly right using the manual ring or with the Capture One micro-AF tools. This is quite difficult to do when hand-holding the camera, so we often found ourselves stopping down to cover focus errors. Focus calibration per-lens is very important.

The resolution of the sensor is particularly unforgiving of focus errors and of a less-than-perfect subject: everything will show. The amount of detail it can capture is astonishing, but what I appreciated more was the 3D quality that so many pixels dedicated to a tonal transition can create. The curve of a ceramic pot or a person's cheek is described not only in the greatest physical detail but also in tonal and color detail, and that really adds something to the image.

One of the greatest elements of the back is the dynamic range though, which allows the deepest shadows and the brightest highlights to be recorded in a single frame and made visible (via tonemapping) in the fabulous Capture One software. The need for neutral density graduated filters with this camera is greatly reduced, and it is actually quite difficult to get an exposure so wrong that a decent image can’t be produced: just like the days of color negative printing (albeit print film was much better at recovering detail from over-exposed areas, while digital is far better at lifting information from the shadows).

As shot Processed from Raw in Capture One

While the extent of the dynamic range is significant enough on its own, having it coupled with the refined highlight warning system allows one to really make the most of it in ways that other cameras don't allow. Knowing precisely how bright you can make the exposure without losing vital information in the highlights lets you expose to the right by exactly the right amount. This naturally brings shadow tones up in the process, yielding cleaner, less-noisy results.

The 100MP back offers 16-bit Raw capture, which theoretically provides more dynamic range than might have been possible with 14-bit capture, assuming the sensor itself is up to the task (that is, if pixel-level dynamic range is greater than 14 EV). Indeed, we found the 16-bit files out of the camera to have so much color and tonal information as to make dramatic manipulations possible, thanks to the incredible resolution and dynamic range. You can shoot in 14-bit mode, which speeds up the internal processing but I shot 16-bit the whole time and didn’t notice any delays.

Noise control in low light is quite remarkable, as one might expect from the large sensor's ability to gather a significant amount of total light. Pixel level noise at even ISO 12,800 is relatively well-controlled, albeit not recommended if if you're looking for giant, clean prints. For that, you'll want the stunning detail at base ISO. Still, low light performance, when normalized to common viewing size, exceeds every camera in our test scene. At ISO 12,800, resized IQ3 images show less noise than the Pentax 645Z, the Sony Alpha 7R II, or even the full-frame low light champion, the Nikon D5. Again, no surprise, given the massive sensor size. But no small achievement, either.

Summing up

I was really pretty sad to see this camera go back, as during the time we spent together I discovered that there is more to having 100MP than just the amount of texture such a sensor can record. The tonality and color of the images are something else, and their flexibility can’t be approached by other sensors. The size of the sensor and pixels just allows it to collect so much data, and all of it contributes to improving image quality.

Many will complain that this sort of resolution is overkill, as they did when we hit 6 million pixels, 10 million pixels and 24 million pixels. Now we see resolutions from ten years ago in a new light, and as we accept progress we wonder how we coped before and wonder at how we were so happy with less. It is inevitable that there will come a time when 100MP sensors appear in 35mm-style DSLRs, and there will come a time perhaps when we will wonder how we coped with 'only' 36 or 50MP.

This IQ3 100MP back is perhaps a taste of what is to come, though we won’t all be using sensors with these physical dimensions. Some will though, and as medium format moves towards its old level of popularity we could see prices drop even more and these cameras fall into the reach of enthusiast photographers.

For now though, the combination of the Phase One XF body and the IQ3 100MP is pretty sensational. The modernization of the body may not be complete, but it is infinitely more useable than the 645DF+ and provides a far better experience than other similar form-factor medium format cameras. It is quick and easy to use, and is a pleasure to work with rather than a hindrance. The quality of image the pair produces is quite simply streets ahead of anything else on the market.

Things we like:

  • Amazing detail resolution
  • Excellent color reproduction
  • Massive dynamic range
  • Much more modern body
  • Great vibration-reduction features

Things we don't like:

  • Big and heavy system
  • Single area AF
  • Power-hungry

Phase One has introduced three firmware updates for the XF system since we tested it, adding some features including a focus stacking tool and full electronic shutter. You can read more about them here: