文档介绍：摄影基础知识Ⅰ了解相机的镜头
actively carry out the law on civil air defense education, drawn out of the air defense in Pinglnternal management, improve staff quality. Adhere to the
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
使用自动相机时，利用“夜景场景”模式也可实现相同的效果，因为这种模式使用了较慢的快门速度。
视角
    镜头可以记录的场景大小称为视角（Angle of view）。视角的大小取决于镜头的焦距。顾名思义，广角镜头具有很宽的视角，意味着使用它可记录相机前很大的场景。另一方面，长焦镜头的视角很窄，用于放大远距离处的拍摄对象。
    通常，焦距在14毫米和50毫米之间（胶片相机上的等同值）的镜头可视为广角镜头。焦距大约为50毫米左右的视为标准镜头，焦距大于50毫米的视为长焦镜头。如果3×变焦镜头的焦距在35〜105毫米之间，它就同时相当于广角（35毫米）镜头、标准（50毫米）和长焦（105毫米）镜头。
    下面的几幅照片显示了用不同的镜头焦距拍摄同一场景的效果。观察焦距如何影响拍摄对象的大小。
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
actively carry out the law on civil air defense education, drawn out of the air defense in Pingliang city Building under easy fare, daily special inspection and regulation, overfulfilled the province upper and lower knots of up to 500,000 yuan fee collection tasks. 5, further standardize internal management, improve staff quality. Adhere to the
焦距：30毫
焦距：50毫
actively carry out the law on civi