It is interesting to see that Leica AG decided to forego the industry standard manufacturers of digital image sensors and go with a relatively unknown, European company instead. The new sensor is made by CMOSIS, a renowned European specialist for advanced CMOS image sensors. They developed a high-resolution, high-dynamic-range CMOS image sensor exclusively for Leica Camera AG. The new “Leica M” digital camera launched at Photokina 2012 incorporates the full-custom CMOSIS “Leica MAX 24MP CMOS Sensor” featuring 24 Megapixels across an active sensor area of 36 x 24 mm, corresponding to the full-frame 35mm format. The sensor is the first milestone in a long term, strategic cooperation between Leica Camera AG and CMOSIS.
Guy Meynants, CTO at CMOSIS, Antwerp, Belgium, said "This is the first time that a CMOS image sensor for a 35mm high-end camera was designed, and is manufactured, in Europe for a European customer. Apart from the ceramic IC package the Leica MAX 24MP CMOS Sensor is a 100-percent European product."
The new custom-designed sensor chip is made by STMicroelectronics (STM) in Grenoble, France, using 300mm wafers in their IMG175 CIS technology. The pixel count is 6,000 x 4,000 pixels on a 6 x 6 µm² grid across the active area of 36 x 24 mm.
The sensor for the “Leica M” is based on a 6 x 6 µm² pixel size, resulting in an impressive linear dynamic range close to 76dB. Pixel data are digitized by patented low-power, high-speed 14-bit column AD converters. The sensor features an electronic rolling shutter with global reset and noise cancellation through both analog as well as digital correlated double sampling (CDS) resulting in low temporal and spatial noise and non-uniformities.
STMicroelectronics took special care to reduce crosstalk between neighboring pixels for a wide range of incident light angles. The sensor reduces spatial crosstalk by its very small distance between color filters and photodiodes. Microlenses with a strong curvature and high top height focus the incoming light rays in the center of each pixel's photodiode. This allows the “Leica M” to accept the full range of high-quality lenses in the camera system.
The pixel size of 6x6µm² and a full frame rate of 5fps are state of the art. The 24MP CMOS Sensor also allows Leica to offer full HDTV video recording and a live preview on an M-model camera.
Leica CEO Alfred Schopf said “With CMOSIS, we are very pleased to have found a partner who made it possible for us to design and construct a sensor especially for Leica. Thanks to the special sensor technology and wide pixel aperture from CMOSIS, we can now, and for the first time, offer a digital system camera that is perfectly optimized for use with both M- and R-Lenses”, said Alfred Schopf, Chairman of the Executive Board of Leica Camera AG. Leica is particularly proud of the fact that the “Leica M” employs a sensor “Made in Europe”, as a large proportion of the sensor is manufactured in France and Germany. “At the same time, the extremely low power consumption of the sensor brings added benefits for both image quality and battery life.”