Pierre Le Forestier
The Pentax 645 holds a special place in the history of medium format. With its 6×4.5 cm negative, this system offers a rare balance between the handling of 35mm and the image quality of medium format, developed over more than four decades, from film to digital. Here is the complete guide to the range, body by body and lens by lens.
© Photo credit: Kurt Bauschardt from Edmonton, Canada
Launched in 1984 with the Pentax 645, the system met a clear demand: to offer a medium format camera that handled as much like a 35mm SLR as possible, with autofocus, motor drive and familiar ergonomics, while keeping the advantages of a large sensor (or negative) in terms of shallow depth of field, dynamic range and tonal rendering. Unlike the more studio-oriented Hasselblad or Mamiya RZ/RB systems, the 645 was also aimed at reportage and fieldwork.
The founding body. Basic autofocus by today's standards, but revolutionary for medium format at the time. Fixed prism viewfinder, top speed of 1/1000s, flash sync at 1/60s. Sturdy but fairly heavy, it laid the ergonomic foundations for the whole line.
A major step forward: improved autofocus, LCD display in the viewfinder, and above all interchangeable backs. Faster and more reliable focusing than the original, brighter viewfinder. It is often the recommended body for anyone discovering the system second-hand, thanks to its excellent reliability-to-price ratio.
A refined version of the N: improved focus lock, finer exposure compensation, better dust sealing. The differences from the N are marginal for everyday use, which is why the N remains much sought after second-hand at a lower price.
Features shared by the film bodies:
Recurring drawbacks: slow autofocus compared with 35mm even on the latest models, a dimmer viewfinder than the waist-level versions of other systems, and reliance on batteries for every function.
© Photo credit: beve4, Flickr
Pentax's first digital medium format camera, after a long development. A 40-megapixel Kodak CCD sensor in 44×33 mm format (smaller than the 6×4.5 film negative but much larger than 35mm). Full weather sealing, a first in this category. Limited sensitivity (ISO 100-1600) because of the CCD sensor and noise handling that could be better at high ISO, but exceptional image quality at low ISO with remarkable dynamic range.
The body that changed the game. A 51-megapixel Sony CMOS sensor, sensitivity up to ISO 204800 (usable in practice up to 6400-12800), tilting screen, Full HD video, much improved autofocus. Weather-sealed and robust, it is still regarded as one of the best-value digital medium format cameras, close behind far more expensive Hasselblad or Phase One systems.
| Body | Year | Negative / sensor | Key points |
|---|---|---|---|
Pentax 645 | 1984 | 6×4.5 negative | Founder, sturdy, basic AF |
Pentax 645N | 1997 | 6×4.5 negative | Improved AF, interchangeable back, best price/reliability ratio second-hand |
Pentax 645NII | 2001 | 6×4.5 negative | Refines the N (marginal differences) |
Pentax 645D | 2010 | CCD Kodak 40 Mpx (44×33) | Pentax's 1st digital MF, weather-sealed, dynamic range at low ISO |
Pentax 645Z | 2014 | CMOS Sony 51 Mpx (44×33) | Best-value benchmark in digital MF, up to 14 stops |
The 645 system has had several generations of lenses, identifiable by their names.
© Photo credit: Jussi You-S-See - Pentax 645
The first generation, with a manual coupled aperture mount. All-metal construction, very sturdy, but without modern electronic contacts. Now sought after by purists for its mechanical simplicity, despite the lack of autofocus.
Introduction of autofocus and electronic contacts. A range covering the essential focal lengths: 35mm, 45mm, 75mm, 80-160mm zoom, 150mm, 200mm, 300mm, and the famous 120mm macro. Construction still largely metal, with a strong optical reputation, especially for the primes.
Optimised for digital: improved coatings against flare and sensor reflections, more modern construction sometimes including polycarbonate parts. Compatible with every body, film or digital.
General qualities of the 645 lenses: the whole range has a reputation for very high optical quality, inherited from Pentax's expertise in aspherical glass and multi-coating (SMC). Sharpness, contrast and flare control are generally excellent, with soft bokeh appreciated for portraits.
Weight and size remain the main criticisms, with some telephotos easily exceeding 1.5 kg. The autofocus motor, especially on the oldest FA lenses, can seem noisy and slow by today's standards. Finally, the choice of focal lengths is more limited than in 35mm, with notable gaps (few very long focal lengths, few very fast apertures below f/2.8).
A major strength of the system is its almost complete backward compatibility: an A-series lens from the 1980s can usually be mounted on a modern 645Z (sometimes losing automatic functions), making it a particularly attractive system for enthusiasts who want to explore medium format on a budget, starting with older lenses before investing in newer equipment.
The Pentax 645 system illustrates a pragmatic approach to medium format: less prestigious in the popular imagination than Hasselblad, less modular than the Mamiya systems, but extremely effective and accessible. The 645Z in particular is still, several years after its release, a benchmark for photographers wanting to move into digital medium format without the sky-high budgets of the competition. The richness and robustness of the lens range, combined with compatibility across generations, make it a particularly long-lasting system in a photography market where obsolescence is usually rapid.
We keep this medium format culture, from film to digital, alive within the collective. Discover the film work of Simon Arcache at Crossed Perspectives #1, Sound and Vision (31 July - 2 August, Hendaye, free entry), and our guide to the Zenzanon lenses of the Bronica SQ system.
Exhibitions, events, calls for projects and blog articles: get the key news from the Argia Collective straight to your inbox.
Grain, chemistry, light: dive deeper into film photography.
Cookies
We and selected third parties use cookies or similar technologies for technical purposes and, with your consent, for experience, measurement and marketing.
