Medium-format digital cameras, which have larger sensors and higher price tags than even high-end SLRs, didn't fare so well in earlier tests of sensor quality by measurement firm DxO Labs, but Phase One's newly tested top-end technology has risen to the top of the DxOMark Sensor test.
Phase One's 60-megapixel P65+ camera scored 89.1 on the test, edging out the Nikon D3X, which scored 88, according to data released Thursday. In addition, the 51.7-megapixel Hasselblad H3DII 50, an older model than Phase One's, scored 78.2. Click here to compare the two models and Nikon's D3X.
The DxOMark sensor test measures a camera sensor's dynamic range, color depth, and low-light performance. DxO Labs cautions that differences of less than 5 points aren't really distinguishable, and of course many other factors including price, lens quality, autofocus, and resolution factor into overall camera quality.
The P65+ features the best color performance yet, but DxO Labs said its comparatively good performance in low-light conditions helped it carry the day.
"This Sensor Plus mode utilizes a binning method: The analog signals of 4 photosites are combined to obtain single pixel after digital conversion. This well-known technology allows for higher sensitivity, but with a loss of resolution (1/4). Only very high-resolution sensors can provide this option," DxO Labs said.
DxO Labs bases its scores on the unprocessed raw images from the image sensors, not the more limited but convenient JPEG images that cameras also produce.
DxO's scores haven't been met with universal acclaim. In response to some criticisms and in an attempt to dispel some confusion, DxO has published a boiled-down DxOMark Sensor explanation.
For example, the company has this to say about sensor resolution, an issue that arose when comparing medium-format cameras with large, high-resolution sensors to high-end SLRs: "DxOMark Sensor and resolution are two independent metrics of sensor performance. As a consequence, just because camera A has more pixels than camera B (and thus sees more details) does not mean that its raw DxOMark Sensor score will be better. So before comparing cameras with DxOMark Sensor, it is important to first determine the resolution you are looking for."