Phase One 645DF+ with IQ250
www.phaseone.com

This is a field test of the Phase One 645DF+ combined with the IQ250 digital back. The back can be used with other bodies, just as the body can be used with other backs, but what I will be looking at is the way they work together. It is worth noting at this point that the 645DF+ has recently been superseded by the Phase One XF camera system, which seems a little more modern, and the IQ2 50MP back is now the IQ3 50. Though the XF system is on the way, there are plenty of 645DF+ bodies still for sale. 

Stepping back a bit, we can remember a time not all that long ago when you made your stand as a 'serious' amateur by using a medium format camera. Compacts and SLRs existed of course, but the graduation from 35mm film to roll film in 120 or 220 formats meant that you had really made it and you expected to be treated with respect by your peers. For some it was like being 'made-up,' a sign of advancement, but for others medium format systems were just a means of improving detail resolution and achieving shallower depth-of-field in their images. Nothing changes and, of course, ownership of even the best medium format kit was never guarantee that good pictures would be made – such a purchase though did at least indicate a respectable degree of desire. 

My medium format film journey began with a Lubitel TLR, in the days when they were priced appropriately (£10) for what they are, and I upgraded to the deluxe Yashica Mat 124G when I went to college. When things got serious and I started to begin to earn a living making cameras go click, and I needed interchangeable lenses, I spent £125 and bought a Mamiya 645 J from a small ad in the back of a photography magazine. I loved that little camera, and ever since I've had Mamiya cameras in the family, from the RB67, RZ67, to the 7ll rangefinder, and the 645AF system. 

Apart from the delightful 7ll these cameras were all nice tools – slightly unrefined workhorses that were very good at their job and pleasant enough to use. I mention all this personal journey not only to be able to reminisce about the good old days, but primarily to remember that these cameras are history and, significantly, historic. 

The relevance to this article, of course, is that the Phase One 645DF+ is very much a Mamiya 645AF, with added features and full integration with the Phase One IQ2 digital backs. If it seems strange to you that Phase One has combined today's cutting edge digital technology with an old dark box from 1999 we might note that the 645DF+ is somewhat more accomplished than the original 645 AF. Launched simultaneously by Phase One and Mamiya in 2012, this latest model is more closely related to the last film munching Mamiya 645AFD lll from 2008. 

Phase One IQ250 key specifications

  • 50MP CMOS sensor
  • ISO 100-6400
  • Built-in wireless technology
  • 3.2" 1,150,000-pixel touch screen

Phase One 645DF+ key specifications

  • TTL phase-detection auto focus
  • Shutter speed 1/4000 sec - 60 min
  • 1/1600 flash sync with leaf shutter lenses, 1/125 sec with focal plane
  • Continuous shooting up to 2 fps

Above is a rundown of the system's major specifications, but some of the features are worth calling special attention to. The shutter speed range runs from a remarkable 60 minute maximum timed opening, to a shortest exposure of 1/4000sec, with B(ulb) and T(ime) modes also available. While the maximum shutter speed that can be synchronized with flash is an old fashioned standard 1/125sec, the use of leaf shutter lenses makes synchronization up to 1/1600sec achievable – and there are currently eight leaf shutter lenses in the range to make the most of this feature. 

The shutter can be tripped by one of four methods ranging from the ancient to the very modern – pressing the shutter release button, using a screw-thread cable release, plugging in an electronic trigger cable or via Wi-Fi through the iOS Capture Pilot app. 

With such a large mirror to potentially disrupt the acquisition of fine detail, it's a great thing that a mirror lock-up mode has been included. This can be used manually or alongside the camera's self-timer – which can be customized to create delays of between 2 and 60 seconds. 

There is basically a single AF zone, right in the center of the screen, and manual focus override is easily achieved via the body switch or the ring on the system lenses. 

On the face of it a top drive speed of 2 frames per second doesn't sound like much, but when you experience the 645DF+ in action at that rate, to hear the steam-driven pistons at work and feel the room shake, it seems a wonder it can operate that quickly at all. With the IQ250 back attached though, the frame rate is reduced to 1.2fps as the back can't process the files any faster. 

The camera is driven by its own lithium-ion cell that runs at 7.4v and which has a capacity of 2000mAh, although a 6-cell AA adapter is also available.