Canon EOS 1D Mark III User Guide - Page 12

By having 2 processors handle the workload, image processing is now approximately 1.5x faster; Compact Flash™ access speed is now 1.3x faster, and SD card access is now 2x faster compared to the EOS-1D Mark II N. The extra power of Dual DIGIC III Image Processors has also allowed analog-to-digital conversion to improve from 12 to 14 bits per channel, meaning that tonal gradation for RAW images is now divided into 16,384 separate levels per channel rather than 4,096. When saved as a 16-bit TIFF image, the image retains the full range of tones obtained with 14 bits. Also, JPEG images, at 8 bits per color, are generated from the 14-bit data. Tonal skipping is thereby reduced substantially, improving gradation and overall image quality. Image-processing Sequence Diagram DDR SDRAM 10M CMOS 14-bit A/D conversion Front-end processing circuit Dual "DIGIC III" CF card SD card Noise Reduction Noise reduction for long exposures is equivalent to that on the EOS-1D Mark II N. When [C. Fn II-1; 1: Auto] is set, 1 sec. and longer exposures will undergo noise reduction automatically, depending on the amount of noise detected in the image data. If [C. Fn II-1; 2: On] is set, all 1 sec. and longer exposures will undergo noise reduction. Now, noise reduction for pictures taken at a high ISO speed is provided via [C. Fn II-2]. Although this feature works at all ISO speeds, it is especially effective for high ISO speeds. At low ISO speeds, noise reduction is not really necessary. However, applying noise reduction can reduce noise within shadow areas taken under low light. Hilight Tone Priority This new feature extends the dynamic range of highlights by about one stop and improves gradation within highlight areas. By expanding the range from the correct exposure level (18% gray) to the maximum allowable highlight level, the gradation from the grays to the highlights becomes smoother and loss in highlight detail is minimized. If [C.Fn II-3; 1: Enable] is set, the settable ISO speed range will be ISO 200- 3200. The display will show "2oo" with the zeros in smaller characters. Depending on shooting conditions, noise in the shadow areas may increase slightly. Highlight Tone Priority: ON Highlight Tone Priority: OFF III. IMAGE QUALITY IMPROVEMENTS 12