已经很久没有看见佳能发布新的DO镜片（绿圈）镜头了，佳能DO镜片采用了多层衍射光学镜片，这种镜片同时具有萤石镜片以及非球面镜片的性质，所以使用这种镜片的镜头体积得以有效的控制，并且在光学性能上也丝毫不弱。在9月15日晚，佳能正式发布了EF 400mm f/4 DO IS II USM镜头...
have long time no see Canon released new DO lenses (green circle) lens, DO lens Canon using multi-layer diffractive optical lenses, this lens also has the nature of fluorite lens and aspherical lenses, so using this lens lens volume can be effectively control, and in the optical performance are not weak. On the evening of September 15th, Canon official release of EF 400mm f/4 DO IS II USM lens...
