Tech Directions - December 2007 - (Page 24)

the object is coming in at many different directions, since our pupil is relatively large compared with the wavelength of light. If it weren’t for the lens in our eye, all those different rays of light from a single point of an object would be scattered across our retina, causing confusion. The lens takes all that light and focuses it to a single point, for every point of the object, thereby constructing a focused image on our retina. (See Figs. 2 and 3.) On the other hand, a pinhole is so small, that most of the light that enters it travels in the same direction, so there is much less confusion. Also, it doesn’t matter how far away each object in the view is—all will be in focus. A lens can only focus for a given distance at a time. The muscles in the eye must change the shape of the lens for each distance. For an amazing demonstration to illustrate this effect, have students who wear corrective lenses try this: Look through the pinhole without the corrective lenses in Another pinhole camera shot Howard, a member of the Stuckism Photography group describes his motivation to create pinhole photographs: “There is something special about a pinhole camera. There is a beauty in its simplicity and rawness that technology has not been able to better. There is a timeless quality that can make the most uncomplicated subject seem full of poetry.” Have your students try it—for the science, art, and FUN! Other Topics to Research Camera obscura ● Charge coupled device (CCD) ● Surveillance ● Viewing solar eclipses ● New World Imager ● Fig. 2—Eye without a lens: The pupil is a large hole that lets light from many directions hit the retina many places. bright light (out the window for nearsighted, close up for farsighted). They will be surprised to see how clearly they can see without their glasses or contacts! The only animal with a true pinhole eye is the nautilus, a mollusk distantly related to the octopus, but with a coiled shell. The problem with a pinhole eye is that it doesn’t allow very much light in and there is not as much contrast. Fig. 3—Eye with a lens: A lens focuses light from many directions onto one spot on the retina. Final Thoughts Check out other related resources on the Web. You will find information about other uses in science, spy cameras, charts and equations, history, and simply some beautiful photography. There is something special about the process of making your own camera and the process of making, planning, and producing your own images. It is satisfying and creative, calming and exciting, all at the same time. Wolf Internet Resources http://users.rcn.com/stewoody www.photo.net—history, cameras, formulas www.wikipedia.org www.pinhole.org—exposure guide www.stuckism.com/HowardPinhole 24 techdirections ◆ DECEMBER 2007 http://users.rcn.com/stewoody http://www.photo.net http://www.wikipedia.org http://www.pinhole.org http://www.stuckism.com/HowardPinhole

Table of Contents Feed for the Digital Edition of Tech Directions - December 2007

Tech Directions - December 2007 Technically Speaking Contents Direct from Washington The News Report Technology Today Technology's Past Mastering Computers Is This Op-Amp Any Good? Lab-Built Checker Removes All Doubt Here Comes the Sun! Residential Solar Systems Add Up to Savings Pinhole Cameras—For Science, Art, and Fun! Poster Project Maps Out Design Process Gifts for Geeks E-gallery More than Fun

Tech Directions - December 2007

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