The Lens That Focuses Itself
Ever shoot an out-of-focus picture? Then you’ll be interested in the newest lens from Nikon. It focuses as automatically as your eye, and just as fast. You can just point and shoot at fast-moving subjects from athletes to zebras without giving focus a thought. As long as you keep your subject within the sensing circle in the center of your viewfinder, you’ll get sharp pictures. Any drawbacks? Sure. The lens is k big (11 inches long), heavy (it weighs six pounds including the batteries that power the autofocus mechanism), slow (f/4.5), and you won’t be able to buy one until next year.â€”A. J Hand
How does it work? Like this:
Light reflected from the subject passes through the first group of lens elements and is split by a ring mirror. Some of the light passes through the lens to the film plane. The rest is reflected down to the autofocus mechanism where a condensing lens forms an aerial image. The position of this image will vary according to distance of the subject. A contrast-sensing set of four photocells inside the autofocus system moves up and down the shaft of focused light. Every time the photocells pass through the point of focus (also the point of highest contrast) they send a pulse to the logic circuit. At each up-and-down cycle of the four cells, a clock pulse is fed to the logic circuit as well. A third pulse indicating the current focus of the lens also is transmitted to the circuit. The circuit takes the three pulse signals and converts them to a time signal. The time signal corresponds to the distance between the sharpest image position and the current focus position. An analog circuit and power amplifier actuate a servo motor that shifts the movable lens elements to bring the lens into focus. All this takes place several times a secondâ€”scanning, computing, and refocusing.
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Levers Control Bike Brakes
A FRONT wheel brake, operated from the handlebar and a two-speed rear wheel coaster brake, operated by a lever mounted on the frame, have been developed for bicycle use. The rear brake has a change speed gear which provides extra power on hills, quick pick-up, and more speed. Photo shows fingertip controls.
Things You Never Knew About Your Fountain Pen
A leaky 1884 pen let loose the flood tide of American ingenuity that has kept the world writing.
By Richard Match
FROM Murmansk to Timbuktu the American fountain pen, streamlined, durable and leakproof, is a symbol of U.S. technological excellence. After World War II our trim Parkers, Sheaffers, Watermans, Eversharps brought $400 each on the black market overseas. Today Japanese and Italian street vendors hawk shoddy counterfeits; the Russians turn out imitation Parker 51’s which cost more than the real thing. But American manufacturers make 75 percent of the world’s outputâ€”some 200 million pens a year.
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Coin Operated Phone for Home
TO PREVENT excessive phone bills and to lessen the “Can I use your phone” nuisance, a coin-operated lock can now be obtained for either the French cradle type phone or the standard type. In operation, a nickel is inserted in the slot after removing the receiver from the hook and the plunger is pushed down with the finger.
The device can be applied in a few seconds to all types of standard phones. It is used in offices, stores and homes where, the meter system is employed.
LEONARDO DA VINCI â€”Edison of Yesterday!
TODAY, just four and a half centuries after he lived, Leonardo da Vinci is receiving belated acclamation as one of the greatest inventive minds the world has ever known!
Famous as a painter, sculptor, architect, scientist, engineer and anatomist, it has not been until the last decade that his genius as an inventor has been truly appreciated. To understand just why this side of history’s most versatile man has been so neglected, we must go back to the latter part of the 15th century, about ten years before Columbus discovered America, for it was then that Leonardo da Vinci was at the height of his all-embracing career.
Harpoon-Rifle Spears Fish
POWERED by stout rubber bands, a homemade harpoon-rifle invented by W. M. Edwards, of Miami, Florida, actually spears fish. A slender arrow is tied to the line of a fishing reel under the rifle barrel. Steel springs in the muzzle prevent the arrow from slipping into the water when the gun is aimed.
The idea of a variable speed of light has been around for a while and is still an active area of research. However, I’ve always heard about it in regards to time frames measured in billions of years. I’m thinking that if the speed of light changed appreciably between 1911 and 1931 we might have noticed.
Velocity of Light is Not Uniform
MANY experiments to determine the speed of light have been made from time to time, but the results are not uniform. Yet scientists have said that this is the one uniform thing in the universe. Dr. M. E. J. G. de Bray has concluded that the variations are real, and that the speed of light does vary over a long period; having been at a minimum in 1911, and a maximum in 1931. This may reassure those who were alarmed by Soddy’s suggestion that light might cease to travel at all.
This is a really odd article. The basic proposition seems to be, “Wow those stupid, plodding Chinese sure are smart. How is that possible?”
It is rather fascinating to conjecture on some of these things, to realize that plodding John Chinaman, who seems thick and slow and dense to modern Western culture, should have sought out these truths of nature, these mechanics that we today are using in the iron men of our machine age. And to realize that we haven’t yet extracted all of the value from their applications as in some instances John Chinaman has done with his science.
John Chinaman – His Science
WHERE there ain’t no ten commandments and a man can raise a thirst, there’s an ancient science extant that looks like the very first. We think we’re the only ones who know smelting and hydraulics and ceramics and printing and electricity. But old John Chinaman had a civilized working knowledge of them all so long ago that our ancestors appear to have been dumbells at the time. They were living in total ignorance of a civilization so advanced and so fundamental that even to this day John Chinaman is ahead of us in the application of many things mechanical he has known since Noah built the ark.