Phase One\'s 50-megapixel gives pro photographers CMOS sensor option

Phase One announced a new digital back that for the first time employs a CMOS image sensor and the new 50-megapixel IQ250 is shipping now. Until now, the medium-format camera market stuck with an earlier sensor technology called CCD (charge-coupled device) for converting photons into data. Now this high-end market segment is following the rest of the digital camera industry to CMOS (complementary metal-oxide semiconductor) technology, the same manufacturing approach used to build conventional microchips. The IQ250's new Sony-built sensor offers options for medium-format shooters, including high-sensitivity performance up to ISO 6,400; exposures as short at 1/10,000th of a second and as long as one hour; and a dynamic range spanning 14 f-stops for a better ability to capture details in both shadows and highlights. It doesn't take advantage of CMOS sensors' superior ability to shoot video, but that's no surprise or even shortcoming given that Phase One sells machines designed solely to capturing the best still photos possible. Medium-format cameras use larger image sensors then even high-end conventional full-frame SLRs like the Nikon D800 or Canon 5D Mark III. Those full-frame SLRs' sensors measure 24x36mm, whereas Phase One's top-end IQ280 uses an 80-megapixel sensor from Teledyne Dalsa that measures 53.7x43.4mm. The IQ250 uses a significantly smaller sensor, though, measuring 44x33mm, which means lenses will have a somewhat narrower field of view. And it only captures 14 bits per pixel data, compared to 16 bits per pixel for the IQ280 and IQ260. However, its 14-stop dynamic range is a notch better than IQ280's 13-stop range, and Sony has been doing a good job with sensors it's supplied to Nikon and itself. Phase One's core products are digital backs, a module with a sensor housing, touchscreen, CompactFlash slot, and USB 3.0 port that can be mounted onto a separate camera body. That approach can be convenient when a photographer wants to move to a new image sensor but doesn't want to pay for a new camera body, too. Medium-format cameras are generally for dedicated professionals with big budgets. The IQ 250 costs $34,990 -- a high price but still short of the $36,990 60-megapixel IQ260, $44,990 IQ260 Achromatic that shoots only black-and-white images, or the $43,990 IQ280.