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The emergence of a new generation of cost-effective HDTV acquisition systems spurred Canon to create a new category of portable lenses to better match the price performance ratio of these cameras. This led to the introduction in 2006 of the new HDgc lens series. Specifically targeted for HD ENG, these lenses retained the optomechanical robustness and ergonomics of the high-end HDxs lens series as well as the same digital drive units. Canon mobilized contemporary design tools and optical materials that facilitated a significant cost reduction while still maintaining an impressive overall HD imagining performance. In recognition of the continuing introduction of new improved 2/3-inch HD acquisition systems and supported by a global experience, Canon is now introducing a second generation HDgc that reflects further design optimizations. The first of these new lenses is the KJ17ex7.7B.
Optical Performance of HDgc Series Aberration Correction for HDgc Lenses
In the HDTV system the pixel size is about half. Therefore, the spread of a point image caused by a spherical and even if the image is slightly out of focus, the MTF is greatly influenced as shown in Graph 1. HDgc greatly contributes to correcting and minimizing these aberrations at the same time maintaingng high MTF throughout the edge of the picture.
Special Optical Elements
With the goal of minimizing chromatic aberration, the HDgc series lenses utilizes special elements including an artificially re-crystalized element, ''Fluorite'', with extraordinary dispersion characteristics and the newly developed ''Hi-UD'' (high index ultra low dispersion) glass. Canon has succeeded in the practical use of special elements along with advanced design techniques like ''separate achromatism''.
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