Professor Bob Newman looks at Nikon’s new D cameras and asks, ‘Who made the sensors?’
Nikon has introduced an interesting pair of cameras in the D5 and D500. The brand has a history of shopping around for its sensors, so it is quite natural that with any release from this company, there will be a flurry of speculation over the sensor source.
A Nikon representative is on record as saying that the two sensors share the same architecture, which some have taken to mean that the manufacturer is the same.
The D5 sensor seemingly originates from the same design team that produced the D4 and D3 sensors before it. Design teams have a tendency to establish their own practice, and so will develop products that have common features, both at a microscopic and macroscopic level. The common features between this new sensor and the older ones are quite apparent.
At the same time, from an exterior view, it seems these sensors have features that Nikon’s own have not previously had – most interestingly, a column-parallel analogue-to-digital converter of the type that gives other manufacturers’ sensors, including Sony’s, exceptional performance with respect to characteristics such as dynamic range.
It is more likely that Nikon has acquired this piece of intellectual property rather than developing it from scratch. In the past, converters such as this have required some years of continuous development to reach the very best levels of performance, which is surely what Nikon would demand for its flagship model. Speculation remains as to the original source of the property.
The D500 sensor, meanwhile, is completely different from that of the D5 and, to my eyes, it clearly emanates from a different design team. Since the sensor does not match the specification of any existing commodity part, determining its likely source requires a little detective work.
Nikon has not yet released the usual front-on sensor photograph for this camera. It has, however, released an arty side-on view, and, looking at this, I find that the sensor it matches most closely is the 1in sensor in the Sony Cyber-shot DSC-RX100 Mark IV. This sensor is a back-illuminated stacked unit. A stacked sensor is one that’s constructed from a ‘stack’ of two or more chips that are piled up rather like a stack of breakfast pancakes. The top chip provides the pixel array, while lower chips provide the peripheral circuitry.
There are a number of advantages to this construction, but perhaps the major one is that each chip can be optimised for the purpose that it serves, providing faster read-out, among other attributes. If this does indeed prove to be a stacked sensor, it will be the first at APS-C size (advanced photo system type-C) in a consumer camera – although Sony has already put such a sensor in one of its cinema cameras.
Bob Newman is currently Professor of Computer Science at the University of Wolverhampton. He has been working with the design and development of high-technology equipment for 35 years and two of his products have won innovation awards. Bob is also a camera nut and a keen amateur photographer