在2014年5月17日的托福阅读考试中有这样一道题：针孔摄像机。针对这道托福考题，出国留学网(m.liuxue86.com)小编来为大家普及一下关于针孔摄像机的背景知识，这样有助于考生在面对这类题目时方便作答。小编在此提醒大家：TPO中，与本文在题材与结构都非常相似的文章是TPO22的The Birth of Photography.这篇文章的第二段第二句提到了camera obscura。
托福阅读真题再现：
版本一：第二篇是讲摄影暗盒技术obscura，一个叫hockney的英国当代画家研究了400个画家来证明中世纪的人用暗盒来辅助画画，以维米尔为例子。讲了他的画如何被认为是使用了该技术，后面提到了一些画家都使用过，还总结了一幅画中使用了该技术的特征，最后说了这个技术并不能抹杀画家本身的实力。
版本二：一开始说了相机成的像是倒置的(标题旁边图 类似小孔成像)。后面通过实验研究发现用镜子可以改变倒置的像。接着说了对艺术家的影响，具体举了一个画家的例子，说他的画可能就是受了相机的影响。但是由于没有对此的记录，作者觉得大概是这个画家不想让大家知道他受了相机的影响。接着又说到了很多画家也可能受到了相机的影响。最后一段说即使相机出现 但是画家还是要有自己在画画上的造诣 并把这些与相机的特点结合起来。
版本三： 有些画家没节操，用小孔成像技术画画还不让别人知道，然后他举了个例子说有个荷兰的画家，叫VIE神马的(达芬奇?)，画画不让人家看也不收徒弟，可能就是因为它利用了这个技术。不过作者后来又说，其实有时候这个技术没啥用，因为最后还得看个人。
词汇：camera obscura n.针孔摄像机
解析：本文围绕针孔摄像机的发明对于油画艺术的主要影响主题为展开论证。文章从三个角度切入，探讨针孔摄像机对于油画艺术的影响，这三个角度恰恰是最后一题文章总结题的三个答案。每个观点独立成段且每段有清晰的主题句的可能性非常大。TPO中，与本文在题材与结构都非常相似的文章是TPO22的The Birth of Photography.这篇文章的第二段第二句提到了camera obscura。
托福阅读相关背景：
Camera obscura
This article is about an optical device. For other uses, see Camera obscura (disambiguation).
A drawing of a camera obscura
Camerae obscurae forDaguerreotype called "Grand Photographe" produced by Charles Chevalier (Musée des Arts et Métiers)
A projection of an image of the New Royal Palace in Prague Castlecreated with a camera obscura
The camera obscura (Latin; camera for "vaulted chamber/room", obscura for "dark", together "darkened chamber/room"; plural: camera obscuras or camerae obscurae) is an optical device that projects an image of its surroundings on a screen. It is used in drawing and for entertainment, and was one of the inventions that led to photography and the camera. The device consists of a box or room with a hole in one side. Light from an external scene passes through the hole and strikes a surface inside, where it is reproduced, rotated 180 degrees (thus upside-down), but with color and perspective preserved. The image can be projected onto paper, and can then be traced to produce a highly accurate representation.The largest camera obscura in the world is on Constitution Hill in Aberystwyth, Wales.[1]
Using mirrors, as in the 18th-century overhead version (illustrated in the History section below), it is possible to project a right-side-up image. Another more portable type is a box with an angled mirror projecting onto tracing paper placed on the glass top, the image being upright as viewed from the back.
As the pinhole is made smaller, the image gets sharper, but the projected image becomes dimmer. With too small a pinhole, however, the sharpness worsens, due to diffraction. Some practical camera obscuras use a lens rather than a pinhole because it allows a largeraperture, giving a usable brightness while maintaining focus. (See pinhole camera for construction information.)
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