No. It is because the F1.7X has its own moving glasses to achieve AF. Since the travel distance is limited, pre-manual focus is required for telephoto lenses.是什么意思_No. It is because the F1.7X has its own moving glasses to achieve AF. Since the travel distance is limited, pre-manual focus is required for telephoto lenses.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句