I like that MAKE contributor Steve Lodefink is suggesting you buy this “gargantuan lens” from American Science & Surplus (for $10.95) if for no other reason than it’s badasss and will look cool weighing down your desk. Or, you can kick it old school (optically-speaking) and build an opaque projector with it. What’s an opaque projector, you say? Ask an old person, anyone who went to school in the middle of the 20th century. It was a precursor to the overhead projector, which was a precursor to the video projector. It was commonly used to project (and enlarge) book art and other reference material onto walls and art media for tracing purposes. Stephen has a link to PDF plans for such a projector on his site. He plans to build one and document the effort.
Make an Opaque Projector – Link
8 thoughts on “Huge lens: project or paperweight?”
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Sounds like a cool idea. Though I must say, I’m a bit turned off by the incandescent light bulb. I have visions of using high-power LEDs to do giant separations.
I used to have this same lense, or one really similar. Made by Siemens. Came out of an ancient gargantuan ex-government laser printer, or so the salvage guy said.
A friend and I used three struts and an old car air cleaner assembly with the end hacksawed off to attach it to my old 1958 vintage Tektronix vacuum tube oscilloscope.
It was slide adjustable for focus, and would project the image from the old CRT a good 15 ft.
I’ve used similar lenses from AS&S, and other places, to build Copyscopes.
http://www.panix.com/~reynolds/astronomy/copyscope/
A surplus lens, some plumbing fittings, and assorted bits can make a nice, inexpensive, and portable wide-field telescope.
CRT projector lens are of similar size but they have really short focal length, less than 5 cm, the diameter of these are usually more than 3″, I had use one to build a video projector with a 2.5″ LCD brought from eBay. I had use white LEDs for lighting source, but I think focused halogen lamps unit would be well too. Great for weekend projects.