The last 21 years have seen dramatic change in the photographic industry, not least in the area of professional photography. When once it would have been unthinkable to work with a system essentially derived from an entry-level consumer format, APS-C digital cameras have become ubiquitous. Meanwhile, the seemingly eternal discussion about which professional medium-format system was best - with Bronica users up against Rollei, Hasselblad, Mamiya, Fujifilm, Contax and Pentax - has come to an abrupt end, highlighted by the disappearance of some of these companies.

A couple of them, however, are doing particularly well right now. Hasselblad has become a focused digital force, with integrated bodies and backs produced with Fujifilm and Imacon technology. Mamiya's flirtation with the innovative ZD DSLR and low-cost ZD back forgotten, the 645 DF sees a strong partnership with Phase One. As such, until recently there were really only two major players in the medium-format digital sector.

But the recent arrival of the Pentax 645D challenges the status quo and the high-end DSLR market. Leaf, meanwhile, has found new life since its acquisition by Phase One, which will apparently maintain its independence as a brand, and the Rolleiflex Hy6 may yet rise from its premature grave. With a range of digital backs still available, including low-cost Multi-Shot solutions, there's still a market for it. Another contender, Leica's S2, is unique in that it has no historical predecessor and no 6×4.5 ancestry. The 30×45mm sensor comfortably qualifies for the modern perception of a medium-format digital however and, with 37 megapixels, it's well above current 35mm DSLR resolutions.

Recent movement in the medium-format digital marketplace has seen the main drawback - cost - eroded somewhat. It's now possible to get a system with an 80mm lens and a decent resolution advantage over the highest-end DSLRs for (just) under £10,000. That headline figure is dominated slightly by Hasselblad's announcement of the H4D-31 at £8,995 +VAT, although anyone shopping for one of these systems will no doubt have seen special offers, trade-in deals and package promotions that have seen medium-format digital systems as low as £7000. The crucial thing is that the psychological barrier of a sub-£10K RRP has been broken and will now be the starting point for such deals, rather than the end point.

This activity may well have been stirred up by the camera equivalent of the Great Prophet Zarquon - Pentax's 645D. First announced in 2004, it finally appeared in Japan in mid-2010 (where it sells for around £7000), and is now heading for the UK with a price of £9190, or £10,212 with a 55mm f/2.8 SDM lens.

Rapid advances in the prosumer DSLR market, and slow development at the high end, have closed the technological gap between entry-level and pro bodies - and, perhaps, pushed professionals to look for equipment that delivers results and identifies them as working with more specialised tools than the average enthusiast. Until there's clear ground between sub-£2000 models such as the 5D Mk II and the flagship bodies, there's a vacuum waiting to be filled - the image quality available with medium format is as compelling now as the move to full frame from APS-C was a handful of years ago.

The first real push to tempt DSLR beyond 35mm came from Mamiya with the ZD, a camera that offered unprecedented resolution and a taste of the lush bokeh and sharpness delivered by larger formats, and the absence of anti-aliasing filters. Regrettably, it was too slow to meet the expectations of DSLR users, and too limited for most already using digital backs, and even the small premium over the full-frame Canon EOS 1Ds Mk II made no sense when the Nikon D3x and EOS 1Ds Mk III appeared a few months later.

Leica S2
Chronologically then, it's the Leica S2 that stepped in to fill that space - albeit in a very different form. Announced at Photokina in September 2008 and shipping roughly a year later, the S2 is relatively unusual; the announced specification made it through to production reality in a reasonable timescale. The S2, as well as continuing the S designation introduced with an early scanning-camera system, essentially replaces the R-series as Leica's SLR offering, and uses a completely new lens mount.

Offered initially with four focal lengths, in standard or central shutter variants (f/2.5 Summarit-S in 35, 70 and 120mm Macro, and the f/3.5 Tele-Elmar-S 180mm), the S2 features a 3:2 ratio, large-sized sensor, it is Leica's first AF system and has the ability to use CS lenses for fast flash sync at 1/500s, or focal plane shutter for quick 1/4000s exposures. The body is designed to be as compact as a pro DSLR and delivers on that, with easy handling and an incredibly robust feel. Prices begin at £17,000, with lenses between £3000 and £6000; so a typical package of an S2 with the 70mm is around £21,000, with the "P" option upgrading to sapphire-glass screen and upgraded customer service.

The S2's engineering is considered - a single AF point, bang in the middle and marked with a crosshair works well with the substantial viewfinder and incredibly fast AF. It's very easy to shoot, compose and judge when your image is not as you hoped. Manual focus is easy and beautifully geared; a split-image screen is available for traditionalists.

The shutter sound is well damped and quiet, while the smaller body and sensor allow the reflex mechanism to be lighter and less obtrusive. As a unique format, the possibilities for lens design are wide open (as the f/2.5 speeds imply); Leica may well be able to leverage the optimised lens and image area to deliver wider, faster glass than 645-derived systems. At launch, a 24mm f2.8 was announced, and it appears that adapters for Mamiya, Pentax and Hasselblad V lenses are in the works.

It's almost irrelevant to go into the image quality. Nearly all medium-format digital systems feature 16-bit capture from colour filter array CCD sensors without AA filters; the S2's custom-designed Kodak unit delivers exceptional colour and sharpness by working with those Leica lenses, aided by fast, accurate AF when appropriate. Where the S2 rises above is in the solidity of the design, the cleverness of the implementation; from a continuous 1.5fps shooting capability, to the push-fit locking tethered cable and the smart OLED top display, which changes colour to deliver different information. The minimalist controls work so well that you can develop a rapid, instinctive control of the camera in a very short time; workflow is aided by offering Compact Flash and SDHC storage with the added ability to write JPEG and raw to separate cards.

The Leica's cost is a little higher than a medium-format system of around 39-40 megapixels, but it's also a very different solution. Leica is looking seriously at the commercial market, where the S2 should comfortably find homes with fashion and portrait photographers, as well as wealthy enthusiasts - and rental and training will feature in that, making working with the S2 easier for many commercial photographers. The ability to use central shutter lenses (due in early summer) will deliver the handling of a DSLR while retaining flexibility usually associated with studio cameras.

Pentax 645D
Arriving after the S2, but announced many years previously, Pentax's digital follow-up to its popular 645 film camera leapfrogged the competition in some aspects during gestation. What Pentax started delivering in Japan last summer, and previewed for European users at Photokina last year, is a very different animal, and on price alone it already presents very strong competition. The 645D's real advantage as an upgrade from 35mm is familiarity and convenience; aspects that users of APS/35mm DSLR systems take for granted.

Read BJP's review of the Pentax 645D

But probably the most significant feature that the 645D brings to the market is the 11-point AF, backed up by the supersonic focus motor in a weatherproof lens. Nothing else currently on the market offers such familiar specifications, and it allows the Pentax to feel like a point-and-shoot consumer-level camera to use. Allied to this are 77-segment metering, in-camera JPEGs with selectable picture modes, and even such tricks as in-camera HDR. It also uses two SDXC cards for storage - a little "amateur" in feel, but surprisingly handy when your main location system has a built-in SD card reader.

It feels a little smaller than a Nikon D3 to handle, and has an interesting body design: the grip, as with a DSLR, is aligned with the back, but the substantial mirror box protrudes, lending it the appearance of an oversized bridge camera. It also features horizontal and vertical tripod mounts and a row of buttons on the top that any musician will find suggestive of an electronic Ocarina; they allow a rapid selection of functions and are a clever feature when you're familiar with the body. Currently there is only one lens that brings the best out of the camera's functions - the 55mm f/2.8 SDM, an inexpensive (by medium-format standards) and, for the price, impressive lens that suggests parent company Hoya should be able to deliver a pleasing range if the system takes off. Older Pentax 645 MF and AF lenses are compatible, but will take longer to focus.

A lot of the user-friendly nature of the 645D is the result of a shared lineage with Pentax's K-series DSLRs; the software and features are very similar, including the image pipeline. This is where the 645D falls slightly short - the 14-bit readout from the 4:3 ratio 40-megapixel CCD (which is treated to 16-bit processing in other installations) is inherently throwing away some of the advantages of a large CCD sensor, and my own tests and raw files suggest a softness from the demosaicing process that I've also seen from Pentax's latest DSLRs. Noise at high ISO is well controlled, with sensitivity priority mode offered - but it does seem to lack the bite and ultimate sharpness that the more experienced MF users will be accustomed to.

Until a full range of SDM lenses arrives, and with allowances for this being "Version 1", the Pentax is an interesting competitor for the high-end DSLR mindset, and one that few Canon or Nikon users will be unhappy with. It allows familiar shooting techniques while introducing the feel of medium-format images and prints. By comparison with medium-format systems, the feature set is far ahead. The raw processing available to the 645D is still in the early stages, so the image quality may well improve - new firmware recently allowed faster, higher capacity SDXC cards for example, addressing the inevitable bottlenecks when writing a 40-megapixel file.

Hasselblad
The bulk of sales for medium-format digital to date have been on the back of studio-based, high-end systems, typified now by Hasselblad and Phase One. Even so, both of those makers have moved much closer to the budgets associated with 35mm DSLR systems at the highest end - and, with years of production, buying secondhand is not a significant drawback.

Hasselblad chose to close its system to third party manufacturers. Should photographers prefer an open system?

Hasselblad's latest H4D system is an evolution of the H3D, with the most distinct change being the new yaw rate sensor True Focus technology that uses the single point AF sensor and calculations to correct focus when recomposing the shot. It's effective and simple to use, while being a deviously clever solution to only having one focus point. Aiming to improve the AF performance offered by the 1-19 EV range AF sensor and typically f/3-4 lenses, the H4D's focus assist light is now white rather than red. Everything else is business as usual, with backs and bodies paired and locked to each other, extremely stylish industrial design with the grey-painted metal body incorporating clever features. These include the grip being the single battery, and a pop-up fill-flash useful for controlling slave systems, while retaining a style link with the old waist-level finder of the 500 series and a wide range of accessories such as GPS module.

The H-series bodies use leaf shutters, giving the system a maximum shutter speed of 1/800s, and the H-system has a range of dedicated lenses including a couple of digital models designed for the smaller sensor area. The H lost the ability to be a film camera after the H2, while also dropping compatibility with third-party backs. There's a trade-off; the H3D/H4D's overall level of integration approaches that of a pro DSLR with the informative viewfinder display, menus and dot-matrix top LCD that can display a quick histogram, but if you buy an H4D-31 now, you can't simply change backs to upgrade when you need to. A trade-in scheme does exist though, but it's not as generous as Phase One's current offerings.

Hasselblad's strengths lie largely in the support and backup, and the brand recognition among the client base which will, at the very least, recognise that you have some expensive equipment. From the user's perspective, the weight of the camera can be uncomfortable for anyone accustomed to a DSLR, and the battery life from the small (1850mAh) grip-style power pack is remarkably short. It powers the body, back and lenses, it has to fit a certain dimension - there's nothing unusual about the rate of consumption, but you will want to carry a couple of charged batteries with you. Fortunately they're rapidly changed over.

Hasselblad's HCD lenses are really the weakest point of the system. Having built a reputation with near-flawless Zeiss optics in the 20th century, the newer Fuji-made lenses feel compromised, yet are relatively large and heavy. The pricing is fair, with most lenses sitting around £2000 (the useful 35-90mm is more expensive at £5500 or so, yet it has a wiry bokeh in the corners and loses sharpness). Phocus, the dedicated raw processor, introduced corrections for the 28mm f/2.8 originally - yet other manufacturers have not needed to resort to such degrees of correction as a matter of course.

The strengths of a mature platform, a recognised brand and a wide support base (including subsidised London studio rental, straightforward operator and equipment rental and so forth) make the Hasselblad a very strong contender for commercial photographers. As an alternative to a DSLR for the sole operator or enthusiast, it's a big investment - and not just financially.

Phase One
Phase One is a relatively young brand, though a veritable powerhouse in the world of high-end digital imaging thanks to the joined forces of the Mamiya 645 system it has based its complete packages around, and Leaf's technology being added to the portfolio. This wide-ranging stance allows it to straddle both the entry-level and the high-end; the Mamiya DM22 is a 645 DF with a Leaf 22-megapixel back, while Leaf's 80-megapixel Aptus-II 12 is the highest-resolution digital back currently on the market. In fact, with a Mamiya 645 DF or AF of the right generation, you have access to 15 different backs, including rotating sensors and pure monochrome models.

Read BJP's test of the Phase One 645DF camera system

Adding to that flexibility, the 645 DF has a focal plane shutter, with a maximum speed of 1/4000s, and the new Schneider-Kreuznach leaf shutter primes can operate at 1/1600s - a speed matched by the flash synch of the new V-Grip Air. The 645 DF body presents something of a dilemma - it can feel dated by DSLR standards yet, as a system body, it's one of the most advanced, with three AF points operating from 0-18 EV (better low-light AF), tethered control, and firmware upgrades via the V-Grip. Powered by six AA batteries, the flexible body doesn't even share power with the backs - the P30+ I used being powered by a 2600mAh battery that contributed to a very useful runtime for shoots.

In terms of image quality, the sensors on the Hasselblad and Phase One are capable of delivering almost identical results - unsurprisingly. Like-for-like comparisons of the P30 and H3D-31 backs will reveal little difference in the best conditions and with good technique. Between the two cameras though, the lighter lenses and integrated AF motor of the Phase One, the yaw rate sensor True Focus of the Hasselblad and the accessibility of controls, all make a difference to first impressions and workflow. Commercially, Phase One's trade-in/upgrade, rental schemes and flexibility make it a compelling long-term investment, with the entry point being one of the cheapest for a brand new system at £6995, while still allowing access to higher-end backs as required.

The custom functions and simplicity of the 645DF make it a great enthusiast camera too, particularly when the huge range of inexpensive used Mamiya lenses is taken into consideration (not to mention the new leaf-shutter Schneider-Kreuznach optics, which are small, light and impeccably sharp). The shooting technique differs from a DSLR, but the Phase One makes little attempt to disguise that - it's a larger, more mechanical-feeling camera and encourages working in the considered way film users are familiar with. Given the wide availability of backs, it's also useful that the earlier Mamiya/Phase One 645 AF bodies are available from some dealers as a refurbished product at less than £800 (the 645 DF's price tag is around £4000 for the body)- so familiarity with the camera and lens can be accomplished with careful secondhand and rental choices.

Conclusions
Of the integrated, DSLR-style bodies, it's a very tough call. Leica's S2 is fantastic and will not disappoint, but costs almost twice as much as the Pentax, which users migrating to medium-format from a smaller DSLR will find instantly familiar and comfortable. The 645D is very good value and has huge potential - a good purchase if you had previously considered £7000 for a full-frame DSLR reasonable. The Leica is the one to buy when you're already good enough that you don't need to justify the purchase; if you must, then the inevitable high resale value will no doubt help the total cost of ownership.

The modular Hasselblad and Phase One systems should, in theory, offer a cheaper upgrade path and accessibility to new technology; photographers used to the whole body becoming obsolete can see that as an advantage; commercially being able to invest in a lower-end body for your own use then rent the specialist backs as needed, nurtures Phase One's commercial and enthusiast user base. Both cameras have some practical advantages in terms of sensor cleaning and servicing and strong backup and service.

Neither of the system cameras can match the Pentax or Leica for handheld shooting; the former remaining sufficiently close to the K-series in feel that you rapidly forget you're throwing around a £10,000 camera. The considered approach remains best with the others. For a more interactive shooting style though, Hasselblad's retention of the waist-level finder option offers social photographers a much-missed method of engagement and composition with their subjects, as with the S2 and Phase One you feel you are making, rather than taking, a photograph.

With digital sales increasing and technology reaching the level where the lowest-end DSLRs (Nikon D3100, Canon 550D, Pentax K-r) are capable of delivering file sizes and image quality that comfortably delivers for most professional jobs, the distinction between "pro" and "amateur" is getting increasingly blurred. Anyone with any technical knowledge is going to expect better results from a D7000 than a D2H, yet the perception is inevitably going to be that the D2H owner is the professional - in part due to the clear investment being made in tools. I don't think anyone needs to buy better cameras to impress clients, but the lower cost of medium-format digital systems is very tempting, with the creative possibilities offering genuine advantages for those prepared to learn and adapt. 2011 could turn out to be the year of medium format.

Read BJP's reviews of the Leica S2, Leaf's Aptus II 12 digital back, which packs 80 megapixels, Phase One's 645DF camera system, the Pentax 645D, and Canon's EOS-1D Mark IV.