Laser Rangefinders
|
Rangefinder
A rangefinder is an optical device that allows distance to be estimated or measured using triangulation, laser, radar, or other method.
: Rangefinder camera
Category:Firearm sights
fr:Télémétrique
pl:Dalmierz
Rangefinder Camera
rangefinder camera]]
A rangefinder camera is one with a rangefinder that allows the photographer to judge the focusing distance. The rangefinder shows a double image, and aligning the two images of the object focused on gauges its distance. Older cameras may display the focusing distance and require the photographer to transfer the value to the lens focusing ring. Most recent designs are coupled rangefinders - that is, the focus is adjusted both in the rangefinder and in the lens by the same control, usually a ring on the lens. In older designs the rangefinder is separate from the viewfinder; in most newer ones it appears at the center of the viewfinder.
History
The first rangefinder (and the name "Range Finder") was invented by Morris Schwartz and sold by his company Kalart. It was designed as an add-on to the Graflex Speed Graphic press camera: you could either send in your own Speed Graphic for modification, or send the cost of a new Speed Graphic in addition to the cost of the Range Finder and Kalart would buy the camera, add the Range Finder and ship it back to you. (Schwartz also invented several other important photographic devices, including the first flash synchronizer and a system for focussing a camera in the dark which worked on the same principle as the rangefinder.)
Rangefinder cameras were common from the 1930s to the 1970s, but the more advanced models
lost ground to single-lens reflex (SLR) cameras.
The best known rangefinder cameras take 35mm film, employ focal plane shutters, and have
interchangeable lenses. These are Leica screwmount (also known as M39) cameras developed for lens manufacturer Leitz Wetzlar by Oscar Barnack (which gave rise to very many imitations and derivatives), Contax cameras manufactured for Carl Zeiss Optics by camera subsidiary Zeiss-Ikon and, after Germany's defeat in World War II, produced again and then developed as the Ukrainian Kiev), Nikon S-series cameras (with design inspired by the Contax and
Rangefinder Camera
I'm not at all certain about some of the RF-vs-SLR claims, such as that RF cameras are more robust than SLRs. Yes, the M-series cameras are famously robust, but is any other RF camera as robust as, say, a Nikon F2? Come to think of it, is a (Zeiss) Contax less complex than a Nikon F2? But having only anecdotal evidence to go on, I've contented myself with toning down some of the claims a little; I've left them in.
Somebody with a lot more time, energy and knowledge than I should add stuff about leaf-shutter compact 35mm cameras, spring (bellows) MF cameras, etc. etc.
Hoary 14:32, 7 Nov 2004 (UTC)
: I've just pulled the following:
::''Since rangefinder cameras are simpler, they tend to be more durable - while some Leicas are collectors' items which are treasured and protected from the slightest scratch, they are nonetheless capable of withstanding considerable abuse and have been widely used by photojournalists.''
: I've no reason to think that a Leica is more durable than, say, a top-o'-the-range Nikon. -- Hoary 10:34, 2005 Mar 30 (UTC)
Laser
A laser (Light Amplification by Stimulated Emission of Radiation) is a device which uses a quantum mechanical effect, stimulated emission, to generate a coherent beam of light from a lasing medium of controlled purity, size, and shape. The output of a laser may be a continuous, constant-amplitude output (known as ''CW'' or ''continuous wave''), or pulsed, by using the techniques of Q-switching, modelocking, or gain-switching. In pulsed operation, much higher peak powers can be achieved. A laser medium can also function as an optical amplifier when ''seeded'' with light from another source. The amplified signal can be very similar to the input signal in terms of wavelength, phase, and polarisation; this is particularly important in optical communications. The verb "to lase" means "to produce coherent light" or possibly "to cut or otherwise treat with coherent light", and is a back-formation of the term ''laser''.
Common light sources, such as the incandescent light bulb, emit photons in almost all directions, usually over a wide spectrum of wavelengths. Most light sources are also incoherent; i.e., there is no fixed phase relationship between the photons emitted by the light source. By contrast, a laser generally emits photons in a narrow, well-defined, polarized, coherent beam of near-monochromatic light, consisting of a single wavelength or hue.
Some types of laser, such as ''dye lasers'' and ''vibronic solid-state lasers'' can produce light over a broad range of wavelengths; this property makes them suitable for the generation of extremely short pulses of light, on the order of a femtosecond (10-15 seconds). A great deal of quantum mechanics and thermodynamics theory can be applied to laser action (see laser science), though in fact many laser types were discovered by trial and error.
Physics and history
The first working laser was made by Theodore H. Maiman in 1960 at Hughes Research Laboratories in Malibu, California,
Laser
Reorganization
Starting to reorganise, splitting laser from laser applications.
Follow section removed, since it's covered in laser applications:
These properties have many uses in science and technology. (Please list some here as links.) Alternative light sources with all these properties are typically weak and cumbersome.
Lasers are widely used by the armed forces in many applications. Lasers can be set to specific, pre-determined frequencies to correspond with a bomb or missile's tracking system. Because the frequency can be set to a range not normally found in natural light settings it is easy for a homing device to find and home in on the signal. Also, lasers can be mounted to weapons and collumated to line up properly with the barrel for targeting purposes. This is especially useful in night combat environments. Some lasers are not in the visible spectrum, and can only be seen using devices that can see infrared, allowing easy targeting for users utilizing night vision devices.
-- DrBob 2001-09-25
----
Rewritten, to remove redundencies and improve flow -- DrBob
----
Thanks DrBob. The whole rewriting process in the last few weeks has been great. Geronimo Jones (original author).
Radio lasers?
Can you enlarge on the early "radio lasers" prior to masers? Have you got a reference, a name, anything? This sounds fascinating... The Anome
Ho:YAG/Nd:YAG
The hospital I work at uses Holium YAG in the OR for laser surgery (cutting/coag). Is this the same as Nd:YAG or similar? If it is a seperate type of laser, should it be included in the list? Perhaps even in Laser Applications since it is used for surgery? We use other lasers in the OR as well, but the YAG/Holium is the newest. Nurses like it better then the others because it is smaller, easier to transport and can take more abuse without decalibration issues. Appearantly the larger lasers we use can be decalibrated easily if bumped. I'd love to see a section
Lcds | Light Diffuser | London Marathon | Magellan Mapsend Topo | Maple Furniture | Mathematics Jobs | Merchandise Liquidation | Milk Storage | Mohawk Carpets | Ms Pac Man | National Obituaries | New York City Seaport | Nomad Mp3 | Objective Lenses | Ontrack Fix It | Overnighter | Paper Lamp | Penasco | Pharmacy Lamp | Pixley
Laser Rangefinders
Laserjet 2p | Laserjet 3 | Laserjet 4si | Laserjet 8500 | Lasko Humidifiers | Last Longer In Bed | Late Bookings | Late Breaking News | Lathe Tool | Latitude D800 | Latitude X200 | Latte Mug | Lauder For Men | Lauder Pleasures For Men | Lauderdale Lakes | Laughlin Air | Launching A Product | Laundry Bins | Laundry Faucet | Laundry Machine
Laser Rangefinders
|
Laser Rangefinders
|
© THIS PAGE ON Laser Rangefinders, COPYRIGHT 2004 ALL RIGHTS RESERVED -- Some Segments Used from Wikipedia under the GNU Free Documentation License |
|
