One limiting factor is the viewing Angle, which is comparable to using a camera lens: a telephoto lens has a narrower view than a wide-angle lens.

限制因素之一就是观察角度，这与使用照相机的情况类似：长焦镜头的视野比广角镜头的观察角度要窄得多。

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However, after the shock subsides and the person is able to look back through the lens of time, I believe that, in hindsight, that surprise factor will lessen.

然而，一旦相关人感到震撼的情绪平静下来，能够回顾事情经过之后，我相信，以我的后知之明，那种惊诧感会变弱的。

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Diffractive efficiency of Fresnel lens is important factor to evaluate the quality of Fresnel lens.

菲涅耳透镜的衍射效率是评价菲涅耳透镜质量的一个重要指标。

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But it gets better: the Speedbooster also makes your lens wider by a factor of 0.71x, shrinking an 85mm lens to 59mm, for instance -- effectively making your NEX nearly full-frame.

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