Find the complete review of the Phase One IQ250 in an upcoming issue of Professional Photographer magazine.
By Stan Sholik
Through the years, Phase One has advanced the technology of charge-coupled device (CCD) sensors, but the needs of some photographers are incompatible with the CCD technology itself. To address those needs, Phase One is introducing the IQ250 back.
The IQ250 sensor is based on complementary metal-oxide-semiconductor (CMOS) technology rather than CCD, which was abandoned by the makers of professional digital SLR cameras years ago. Phase One is retaining its CCDbased backs and adding to its line with this, and presumably other, CMOS-based backs.
Although the time of year wasn’t optimum and there were distant city lights glowing over the horizon, I was able to capture the Milky Way using an ISO of 6400 and an exposure of 8 seconds at f/2.8 with the Phase One IQ250 and Schneider Kreuznach 55mm f/2.8 lens. [Click for high-resolution image; use arrow keys to navigate around the image.]
The most welcomed feature of the IQ250 for most photographers is its ability to shoot at high ISOs. While the lowest ISO on the IQ250 is 100, the highest is now 6400. Every ISO setting up to and including ISO 1600 is completely usable for all subjects. ISO 1600 seems to deliver about the same tight luminance noise and lack of chrominance noise as my Nikon D700 at ISO 800. At ISO 3200, noise is visible, but Capture One software can easily remove it with minimal sharpness loss. By ISO 6400 it is still possible to eliminate the chrominance noise, but luminance noise is present unless you really crank up the noise reduction. However, in order to shoot the Milky Way with the Schneider Kreuznach 55mm f/2.8 at 8 seconds (to eliminate star trails), I needed ISO 6400, and the result (above) is totally acceptable to me until I enlarge the 8,200x6,208-pixel image to 1:1 on a high-end monitor.