Introduction

Raising the operability of a digital SLR camera to the level of film-base SLR cameras required development of a large high-resolution CMOS image sensor. Digital cameras normally use smaller image sensors than the frame size of 35mm film. When an interchangeable lens is attached to a D-SLR with smaller image sensors, the effective angles of view and perspectives of the captured image differ from the focal length marked on the lens. For this reason, photographers were unable to utilize their experience using 35mm film SLR camera lenses with digital SLR cameras. In 2002 Canon developed a large, full-frame 36 mm x 24 mm CMOS image sensor, which is incorporated in the Canon EOS-1Ds.
CMOS image sensor
The Canon EOS 1Ds D-SLR accommodates the full range of interchangeable lenses available for the EOS series SLR cameras, ensuring faithful angles of view and perspectives according to the focal length. In 2004, a new 35mm full-size large CMOS sensor was developed and this is installed in the EOS-1Ds Mark II. Second-generation large CMOS sensors have a resolution of 16.7 million effective pixels. This is a high resolution said to be equivalent to that offered by 35mm film SLR cameras.
Full frame
Canon's semiconductor production technologies played a major role in the development of the new Canon CMOS sensor. In short, we developed a new partition exposure technology under which each 35mm full-frame CMOS sensor is exposed three times, and each of the exposures is ultra precisely bonded with the others. This method allowed us to produce a large, high-precision CMOS sensor at a relatively low cost.
Data transfer rate
The number of pixels in this sensor is impressive, but how can it scan large volumes of image data at high-speed? CMOS sensors have one amplifier (converter that changes electric charges to voltage signals) per pixel, so they can perform signal amplification on a per-pixel basis. For this reason, CMOS sensors transfer image data faster than CCDs. To achieve even higher speed, Canon developed the new Canon CMOS image sensor to simultaneously read each image element line via eight channels. As a result, read speed was increased to four times that of a conventional CMOS sensor that reads signals through two channels, achieving continuous shooting of 4 frames per seconds (fps). The CMOS sensor has been designed to give greater depth to each pixel, allowing more ample gradations, from highlighted to shadowed portions of images. Each pixel can store more electric charges, allowing a higher saturation point. As such, the dynamic range of the CMOS sensor is on a par with that of reversal film.