The combination of telephoto capabilities and an f/2.8 aperture throughout the zoom range up to 500mm makes this a great lens for wildlife, sports and for you stargazers, astrophotography.

远摄镜头的性能加上f/2.8的光圈，再加上最长500mm的长焦端，使该镜头适合拍摄野生动物和体育赛事，也是天文爱好者进行天文摄影的绝佳镜头。

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Range alignment is crucial in motion compensation of the inverse synthetic aperture radar (ISAR).

距离对准是逆合成孔径雷达(ISAR)运动补偿的关键。

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The simple formulae of fast calculating aperture antenna directivity and gain are derived using antenna beamwidths. Applied range of these formulae are analyzed and discussed.

导出了用天线方向图的半功率波束宽度快速计算口径天线方向性系数和增益的简单表达式，分析讨论了这些公式的应用范围。

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This high performance, interchangeable zoom lens features an F2.8 maximum aperture throughout its entire 15-45mm zoom range and is designed for exclusive use with the PENTAX Q-Mount line of digital cameras.

ENGADGET: Pentax launches Q10 interchangeable lens camera, K-5 II and K-5 IIs flagship DSLRs