Pentax RAW codec enables preview of photos captured as Raw files using the explorer in Windows Vista and Windows 7, without the need to process the files first. The software continues to be compatible only with the 32-bit version of each operating system, and is not currently available for their 64-bit incarnations, nor is any equivalent offered for Apple's Mac OS X. The previous version was released in November 2009, and offered support for the Pentax *ist D,*ist DS,*ist DS2, *ist DL, *istDL2,K100D, K10D, K100D Super, K20D,K200D , K-m (aka K2000), K-7, and K-x digital SLRs. The new release of Pentax RAW Codec includes all of these, plus one further addition -- the 645D medium format SLR, which began shipping in Japan a few months ago. The latest Pentax RAW codec software for Windows Vista and Windows 7 can be downloaded from the Pentax website.

Development of the Pentax 645D was first revealed on March 2005, and by its eventual official announcement some five years later, the design had evolved greatly. The eventual spec sheet encompassed a Kodak KAF-40000 CCD sensor offering 40 megapixel resolution, in a fully sealed body that resists dust, weather and cold to -10° celsius. A variety of other features derived from the prosumer K-7 model including a PENTAX Real Image Engine II (PRIME II) image processor, a Dust Removal II (DR II) mechanism using piezoelectric vibration of the UV/IR cut filter, and a 3.0" LCD display with 100% field of view and 921,000 dot resolution (using a glass cover plate like the Pentax K-7 Limited Silver). Other features inherited from the K-7 include power from a D-LI90 lithium-ion rechargeable battery pack, a selection of USB, HDMI Type-C and NTSC / PAL composite video connectors, EXIF copyright tagging, in-camera HDR, dynamic range expansion and distortion / aberration correction, as well as the Color Temperature Enhancement white balance mode that helps emphasis color of sunsets, etc. The 645D also includes a digital level function, but with a couple of important differences from that of the K-7. Firstly, it's a dual-axis level, rather than the K-7's single-axis level. Secondly, it lacks the horizon correction function, since the sensor isn't mounted on a movable platter.

The 645D's images are metered with a 77-segment sensor offering three modes - multi-segment, center-weighted or spot. There's also an 11-point phase detection SAFOX IX+ AF system with continuous and single operation, and the ability to select points automatically or manually. Like the K-7, images are stored on SD or SDHC cards (but not the latest SDXC types), but the Pentax 645D does include two SD card slots to allow either automatic overflow, simultaneous backup or segregation of images by file type. Eight creative modes like those in the K-7 allow tuning of parameters like contrast, saturation, hue, sharpness, and more, and include a new reversal film option.

Many points where the 645D varies significantly from its sibling -- beyond the medium format lens mount and sensor, and the pro-friendly body with features such as a mirror lock-up knob -- are in its variables relating to exposure. Burst shooting is possible at 1.1 frames per second for 15 JPEG or 13 Raw frames. Shutter speed ranges from 1/4000 to 30 seconds plus bulb (with noise reduction after 30 seconds). Sensitivity ranges from ISO 200 to 1,000 equivalents ordinarily, and can be expanded to a range of ISO 100 to 1,600. There's also no in-body image stabilization, due to the much larger sensor size of a medium format camera, as compared to APS-C models, and no live view or movie functionality, due to the choice of a CCD image sensor rather than a CMOS chip. Images are instead framed on a trapezoid prism viewfinder offering 98% field of view.

The Pentax 645D was initially available only in Japan from mid-May 2010, with pricing of ¥807,620 excluding sales tax (at the time roughly equivalent to US$8,900, ignoring exchange rate fluctuations, taxes and duties.) At the current time, the 645D is not available in North America, and no future plans for sale have been announced in this market.