Although the Pentax 645Z medium format DSLR has been out for a few years, I only had a chance to try it out earlier this year, during my trip to Death Valley. I have been wanting to try the 645Z for quite some time, since I heard so many good things about it. With medium format digital being traditionally out of reach in terms of cost for most photographers out there, including myself, I did not really have much interest in trying out cameras that are as expensive as some nice cars. However, the Pentax 645D changed the game back in 2010, by being the first sub-$10K medium format digital camera at launch.
Earlier this week, Ricoh Imaging introduced the Pentax 645Z, a high resolution 51.4 MP medium format DSLR camera. While Nikon has been relatively quiet on the resolution front with its now 2+ years old 36 MP D800/D800E models and Canon has not stepped up above 24 MP, Pentax is stepping in with a larger sensor that provides super high resolution 51.4 MP images. With its 43.8 x 32.8mm size sensor, the 645Z has a smaller version of the medium format (MF) sensor that is similar in size to the Leica S-System, although with a different aspect ratio of 4:3 vs 3:2. Compared to full-frame sensors, the physical size of the 645Z MF sensor is about 166% (or 1.66 times) larger, which is a huge difference. Enough of a difference to allow for relatively large pixel size of 5.3 microns – bigger than 4.8 microns on the Nikon D800/D800E. Why does this matter, you might ask? Well, that’s because the Pentax 645Z comes with a CMOS sensor, which is similar technology as we see on all modern DSLR cameras. Compared to traditional CCD sensors used on medium format cameras, a CMOS sensor is capable of yielding images with very little noise at high ISO sensitivity levels. As a result, the Pentax 645Z has an ISO sensitivity range of 100 to 204,800, which is a mind-boggling number for a medium format camera.