Pentax 645D £8999.99

25th Nov 2011 | 16:10

Pentax 645D

Pentax's 40Mp medium format camera put to the test

TechRadar rating:

4 stars

Like:

Great build quality; Good ergonomics; Excellent image quality; DSLR-style interface makes it easy to use; High quality LCD and viewfinder;

Dislike:

A little slow when reviewing shots onscreen; Too expensive for the sort of consumer that would appreciate the simple design; AF system becomes sluggish in low light;

Overview

As the manufacturer's first foray into the digital medium format arena, the Pentax 645D brings plenty of appealing features to the game, including a 40MP, 44 x 33mm, Kodak-developed CCD sensor that's designed to deliver professional image quality exceeding that of a 35mm full-frame DSLR.

With a nod to Pentax's original medium format film 645 camera system, the new digital SLR version looks and feels every bit as solid as its well-respected 1980s-born ancestor, sporting a similarly intuitive design. Despite its retro looks, however, the Pentax 645D is equipped with a whole host of up-to-date photography technologies and plenty of advanced functionality: all in an easy-to-use package.

Pentax 645d review

The Pentax 645D has an RRP of £8999.99 for the camera body alone, or just shy of £10,000 to buy it along with the brand new D-FA 645 55mm f/2.8 AF (IF) SDM AW lens. The camera certainly represents a sizeable investment then, yet is still a lot cheaper than medium format digital camera rivals such as the Leica S2. So what do you get for your cash?

Features

With prestigious brands such as Hasselblad, Phase One and Leaf heading up the medium format digital camera market, the Pentax 645D is up against some stiff competition. But Pentax hasn't been deterred from taking on the big boys - both in terms of the technology it has to offer and the price.

Although perhaps still out of the budget range of many professional photographers looking for a product to give them the best image quality they can afford, the Pentax 645D currently represents the most affordable option in the digital medium format market, undercutting its competitors, such as the £21,000 Leica S2, by a fairly significant amount.

The Pentax 645D's headline feature is its 40MP CCD sensor: measuring 44 x 33mm, images reach a top resolution of 7264 x 5440 pixels, giving plenty of scope for some pretty severe cropping if necessary, as well as extremely high-quality large format printing options.

Pentax 645d review

There's also a high resolution, 921,000-dot TFT LCD screen that sports a reinforced glass upper surface, wide viewing angle and effective anti-reflective coating that makes it highly usable.

The clear display and 32x image magnification capability make it easy to check images for accurate focusing and sharpness - a vast improvement over some of the comparatively poor-quality screens we've experienced on other digital medium format rivals.

Other notable features include an 11-point SAFOX IX+ AF system, 77-segment metering system, a crystal clear, all glass, trapezoid pentaprism viewfinder and Pentax's Prime II imaging processor. Plus useful extras include a digital spirit level, automatic lens correction, dust removal, dual SD card slots, 14 Bit raw file support in PEF and Adobe DNG formats, HDMI output and in-camera HDR processing.

The Pentax 645D's comprehensive set of technologies make it well equipped to deal with a good range of photographic situations.

Build quality and handling

Pentax 645d review

It may be big, but the Pentax 645D manages to remain surprisingly light, thanks to an aluminium die cast chassis, combined with its magnesium alloy outer shell. Although you still probably wouldn't want to have it round your neck all day, at only around 200g weightier than your average full-frame DSLR, it is perfectly possible to take the Pentax 645D out in the field for some photography outside of the studio.

With that last point in mind, Pentax has borrowed elements from the excellent design of its flagship DSLR, the K-5, including full weather sealing and the ability to operate at temperatures as low as -10C, so you can be confident that the camera can withstand the rigours of life on the road.

Partnering the rugged build with ergonomically-shaped, rubberised front and rear grips makes the Pentax 645D very comfortable to shoot with hand-held. Its intuitive interface - which borrows heavily from Pentax's tried-and-tested DSLR designs - also makes it incredibly simple to pick up and start using straight away.

Pentax 645d review

The large top-panel LCD screen provides an overview of your current settings at-a-glance, with further information being displayed on the rear LCD.

Underneath the screen there are fast access buttons to the camera's flash, colour drive mode and white balance options, with further controls lining the right-hand side of the screen and spreading out towards the deeply sculpted rear thumb grip towards the right-hand side of the back panel.

Even more buttons - including dedicated controls for accessing each of the Pentax 645D's dual memory card slots - are located on the elongated top panel that extends to the left of the viewfinder hump.

Pentax 645d review

With such a comprehensive array of large, dedicated controls spread across the camera body, you have fast access to all of the key functions you're likely to need while shooting, and - if you do have to delve into the main menu system for any reason - everything is logically laid out and easy to navigate using the camera's four-way d-pad.

The combination of high-end features and such a simplistic design that, arguably, any photographer could easily master - regardless of experience level - is what makes the Pentax 645D such an appealing camera.

Performance

Pentax 645d review

Medium format digital cameras such as the Pentax 645D don't tend to aim to match the blistering operational and continuous shooting speeds of their pro-level DSLR counterparts, so if you're an action photographer - with the Pentax 645D's burst rate reaching 1.1fps - needless to say this isn't the sort of camera that will benefit you.

In operation, the Pentax 645D's sophisticated 11-point autofocus system - which offers nine cross-type sensors - is fast and accurate when working in good light.

In comparison to a high-end DSLR, such a small array of points - which are arranged around the centre of the frame - may seem a little restrictive. However, compared to medium format rivals, which tend to offer fewer AF points, the Pentax 645D looks far more impressive, particularly in that it offers a continuous AF mode that works pretty well, all things considered.

Pentax 645d review

When the light levels drop, however, the AF system starts to struggle, at which point you may find it preferable to switch to manual focusing. Although working manually is perhaps not ideal if time is of essence, the Pentax 645D does offer a helping hand in the shape of a focus confirmation light, which appears in the viewfinder display once a lock has been achieved.

Thanks to the huge files that the Pentax 645D's processing engine has to deal with, the time taken for an image to be written to your memory card can be anything up to just over 10 seconds (raw or JPEG files).

Thankfully, however, you're only locked out of the controls for about a second before you're free to take the next shot. But you will be in for a bit of wait (about 3-5 seconds on average) if you want to check the image you've just taken, which isn't ideal if you're conducting a fast-paced fashion shoot, for instance.

Pentax 645d review

Outdoors, colours captured by the Pentax 645D are true-to-life, with a good spread of tones and hues that pack enough punch to give them a lift, without resorting to over-saturation.

Indoors, the Auto WB does a fairly good job at producing colour-cast free images, but there was the odd occasion where it was necessary to take a custom reading in order to get things looking perfect.

Shooting raw files obviously gives you the most flexibility when it comes to processing, although the level of detail and the colours reproduced in JPEGs straight out of the camera is very impressive. There are in-camera colour adjustment options, including portrait and Landscape settings, plus Muted, Vibrant, Bright, customisable Monotone and a quirky Reversal Film setting.

The 77-segment metering system that we originally experienced in the Pentax K-7 has been put to good use in the Pentax 645D. On the whole, exposures proved to be very accurate, albeit with a slight tendency towards underexposure - although this does lessen the likelihood of ending up with unrecoverable, blown-out highlights and produces an overall richer look to the colours.

Pentax 645d review

When it comes to detail, the Pentax 645D's huge 40MP images never fail to impress. This is - of course - what you pay the extra cash for over a 35mm DSLR: the unrivalled level of image quality that only a medium format sensor can really provide.

By default, JPEGs are beautifully detailed and sharp, although if you prefer total control, then selecting one of the camera's two raw file formats - Pentax's proprietary PEF or the universal-format DNG - is the way to go. A seemingly inexhaustible level of detail can be pulled from both the highlights and the shadows in the Pentax 645D's raw files, and the fact that you have the option of shooting DNGs means that your existing RAW editor will almost certainly enable you to get straight to work on your shots, with no additional plug-ins or software required.

While the Pentax 645D may not offer the same sort of expansive list of ISO sensitivities that we've seen on top-end DSLRs of late, the goal with this camera seems to be to provide quality over quantity.

Our lab tests showed that the Pentax 645D doesn't match up to the signal-noise ratio of two of the current market-leading full-frame models, the Nikon D3x and Canon EOS 1DS MKIII.

But in real life situations, images shot throughout our medium format model's native sensitivity range (ISO 200-1000, with 100 and 1600 being extras) actually look pleasingly clean. At the top settings, noise is visible, but it's film grain-like, plenty of detail is retained and colours remain faithful for the most part, making it perfectly possible to successfully clean up shots taken at ISO 1600 - particularly if you shoot raw.

Image quality and resolution

For a full explanation of what our resolution charts mean, and how to read them please click here to read the full article.

Resolution charts

As part of our image quality testing for the Pentax 645D, we've shot our resolution chart with a Pentax smc D-FA 645 55mm f/2.8 lens mounted.

However if you're wondering why you'd pay the extra for the Pentax 645D, you only have to look at the results for resolution across the sensitivity range. The resolution results at ISO 200 for the Pentax 645D are a staggering 3,600 LW / PH, close to the maximum possible for our charts, compare this to the Nikon D3x's at a still impressive 2,800 LW / PH and the Canon EOS 1Ds MK III's at 2,600, and you can instantly see the benefits of the 40MP medium format sensor*.

* Pentax 645D sensor size 44mm x 33mm, True medium format 50.7mm x 39mm, full frame 36mm x 24mm

Reading the charts

If you view our crops of the resolution chart's central section at 100% (or Actual Pixels) you will see that, for example, at ISO 100 the Pentax 645D is capable of resolving up to around 32 (line widths per picture height x100) in its highest quality JPEG files. However, this rises to 36 (line widths per picture height x100) at ISO 200 and above.

Examining images of the chart taken at each sensitivity setting reveals the following resolution scores in line widths per picture height x100:

Pentax 645d resolution iso 100

JPEG resolution

Pentax 645d resolution iso 100

ISO 100, score: 32 (see full image)

Pentax 645d resolution iso 200

ISO 200, score: 36 (see full image)

Pentax 645d resolution iso 400

ISO 400, score: 36 (see full image)

Pentax 645d resolution iso 800

ISO 800, score: 36 (see full image)

Pentax 645d resolution iso 1600

ISO 1600, score: 36 (see full image)

Raw resolution

Pentax 645d raw resolution iso 100

ISO 100, score: 32 (see full image)

Pentax 645d raw resolution iso 200

ISO 200, score: 36 (see full image)

Pentax 645d raw resolution iso 400

ISO 400, score: 36 (see full image)

Pentax 645d raw resolution iso 800

ISO 800, score: 36 (see full image)

Pentax 645d raw resolution iso 1600

ISO 1600, score: 36 (see full image)

Noise and dynamic range

We shoot a specially designed chart in carefully controlled conditions and the resulting images are analysed using the DXO Analyzer software to generate the graphs below.

For more more details on how to interpret our test data, check out our full explanation of our noise and dynamic range tests.

Our labs data for the Pentax 645D is compared against the Nikon D3x and Canon EOS 1Ds MKIII. While these DSLRs have smaller sensors and are considerably cheaper (although not that cheap), all three cameras are perfectly suited to studio use.

Our analysis shows that all three cameras produce excellent results, but for both noise and dynamic range the Nikon D3x and Canon EOS 1Ds MK III just have the edge over the Pentax 645D.

JPEG Signal to noise ratio

A high signal to noise ratio (SNR) indicates a cleaner and better quality image.

Pentax 645d jpeg signal to noise ratio

Our results for the JPEG images from the Pentax 645D indicate that despite the increase sensor size it generates a lower signal to noise ratio than the Nikon D3x and Canon EOS 1Ds MKIII.

JPEG Dynamic range

Pentax 645d jpeg dynamic range

This chart indicates that the Pentax 645D's JPEGs compare well against the Canon EOS 1Ds MK III up to a sensitivity of ISO 400.

For more more details on how to interpret our test data, check out our full explanation of our noise and dynamic range tests.

RAW Signal to noise ratio

A high signal to noise ratio (SNR) indicates a cleaner and better quality image.

Pentax 645d raw signal to noise ratio

Raw images as with JPEGs from the Pentax 645D show a lower result for signal to noise ratio than both the Nikon D3x and Canon EOS 1Ds MKIII.

Raw Dynamic range

Pentax 645d raw dynamic range

This chart indicates that the Pentax 645D's raw files score well at the lower end of the sensitivity range, however these results are dwafed by the Nikon D3x and Canon EOS 1Ds MK III.

For more more details on how to interpret our test data, check out our full explanation of our noise and dynamic range tests.

Sample images

Pentax 645d review

COLOUR:The Pentax 645D does an excellent job of capturing punchy colours, with the in-camera colour adjustment options providing scope for creativity.

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Pentax 645d review

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Pentax 645d review

EASY:As a studio camera, the Pentax 645D really shines, with easy-to-use controls helping to streamline the shooting process and leaving you free to concentrate on your creative vision.

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Pentax 645d review

HANDHELD: Handheld shooting in natural light is an equally rewarding process. The metering system copes well when it comes to capturing high-contrast scenes.

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Pentax 645d review

OUTDOORS: Outdoors, the Pentax 645D performs very well, with its relatively lightweight construction allowing the freedom to capture subjects in their natural setting.

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Pentax 645d review

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Pentax 645d review

FOCUS: The camera's medium format sensor imbues images shot at wider apertures with beautifully soft out-of-focus areas, keeping the attention squarely on your subject.

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Pentax 645d review

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Pentax 645d review

SHARP: Pin-sharp detail is an enduring feature in all of the 40MP Pentax 645D's shots, regardless of the ISO sensitivity you select.

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Sensitivity and noise

Pentax 645d review

Full ISO 100 image. See the cropped (zoomed to 100%) versions below.

Pentax 645d review iso 100

ISO 100

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Pentax 645d review iso 200

ISO 200

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Pentax 645d review iso 400

ISO 400

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Pentax 645d review iso 800

ISO 800

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Pentax 645d review iso 1600

ISO 1600

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Verdict

Pentax 645d review

£10k is a lot of money for a camera in anyone's book, but when you take into account that the Hasselblad H4D-40 carries an RRP of £14,634 for the body alone, it puts the relatively keen pricing of the Pentax 645D into perspective.

If you look at things from the other end of the market, the Pentax is roughly £2-3k more than the closest-resolution 35mm full-frame DSLRs - the Nikon D3x and Canon EOS 1DS MKIII - but offers a significant increase in sensor size and resolution.

Obviously, there's a difference between the way a full-frame DSLR and a medium format digital camera handles: don't expect the Pentax 645D to keep up with the Canon EOS 1D X in the speed stakes, or to match the Nikon D3S for its superb low-light performance, for instance. What you do get, however, is superior image quality - in terms of resolution - and great handling in a sophisticated yet user-friendly package.

We liked

The Pentax 645D's DSLR-inspired controls make it refreshingly quick and simple to operate, so you can concentrate on getting the very best out of that 40MP sensor.

We disliked

Processing between shots can be a little slow and noise isn't quite as well controlled as it is with its cheaper full-frame DSLR peers.

Final verdict

If your top priority is detail in your images, you love the distinctive shallow depth of field look that a medium format sensor characteristically produces and you don't need the speedier performance or bells and whistles offered by the comparably more compact - and more affordable - full frame DSLR alternatives, then the Pentax 645D is an option that we'd certainly recommend investigating.

It is cheaper than the medium format competition, but perhaps still not quite within easy grasp of the average pro photographer. On the other hand, if only medium format will do and you can stretch your budget, it's the best value package around.

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