相对来讲50 mm镜头比较的便宜。

For the most part, 50mm lenses are cheap.

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只有配用1.5x或1.6x镜头焦距转换率的镜头，方能获得正常的广角效果，不过也不必担心什么，这些镜头已经随处可见，并且比起全画幅的要便宜不少。

With a crop factor of 1.5x or 1.6x you need special digital lenses to get true wideangle results, but these are readily available and are usually less expensive than their 'full frame' counterparts.

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50mm定焦镜头在较大价格范围内的平均光圈是F1.4，便宜的（镜头）光圈为F1.8，较贵的（镜头）光圈为F1.2。

The 50mm prime on average allows an aperture around F1.4 on a mid ranged price lens, F1.8 on the cheaper ones and F1.2 on the pro series.

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