Leica Lens Glossary

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Leica APO- "apochromatically corrected". In most lenses, optical design concentrates the focus of blue light and green light into a single plane, but red light falls slightly into another plane of focus. Red subjects, therefore, would be ever so slightly out of focus compared to blue and green subjects in the same frame. Not sure you'd ever notice though, the difference is so slight. This is the same basic principle that requires you to shift the focus for infrared photography, related to the wave length of red light. In APO lenses, the design and expense has been put in to making red light focus on the same plane as blue and green. Under a microscope you would see that all light subject is now in focus, creating a sharper image overall. Many manufacturers offer APO designs, but in most of these only the very center of the lens is APO corrected. Leica prides itself on making most of the frame APO corrected. 

Leica ASPHASPH - "aspheric design". Most lenses have a spherical design - that is, the radius of curvature is constant. These are easy to manufacture by grinding while "spinning" the glass. This design however restricts the number of optical corrections that can be made to the design to render the most realistic image possible. ASPH lenses, however, involve usually 1 element that does *not* have a constant radius of curvature. These elements can be made by
1) expensive manual grinding,
2) molded plastic,
3) Leica's patented "press" process, where the element is pressed into an aspherical ("non-spherical") shape. This design allows the manufacturer to introduce corrections into compact lens designs that weren't possible before. Practically, the lens performs "better" (up to interpretation) due to increased correction of the image, in a package not significantly bigger than the spherical version. 

There is another Aspherical lens manufacture technique: an uneven coating layer is applied to a spherical lens. The coating is thicker on the edges (or on the center, depending). Canon "Lens Work II" calls these "simulated" aspherical lenses. Simulated and Glass-Molded (GMo) asphericals show up in non-L Canon lenses, while the L lenses have actual ground aspheric elements.

Leica BeamBeam Splitting What happens to light when it moves through R series Leica SLR bodies. Light from the lens is split into two when it hits the reflex mirror — one portion goes through the semi-silvered mirror to the light meter at the base of the mirror box, the rest is reflected upwards through the pentaprism & viewfinder. It's because of this "beam splitting" that you have to use Circular Polarizing filters on R cameras to obtain accurate light meter readings. With linear polarizer filters, phase cancellation effects occur when the light travels through the mirror, resulting in inaccurate and unpredictable readings.

Leica CLACLA An acronym for "Clean, Lubricate & Adjust", where the item is re-lubricated, fine-adjusted and calibrated rather than extensively repaired.

Ernst Leitz Canada, established 1952, was and still is the military/industrial branch of the old "Ernst Leitz Canada". In 1998, the ELCAN plant was sold to Raytheon (USA), who bought it from its previous owner, Hughes Aircraft Co. Elcan-R is also the name of s series of lenses made in the 1960ies and early 1970ies, as the U.S. Navy High Resolution Small Format Camera System during the Viet Nam war.

Leica ElmarElmar - Maximum lens aperture — here ƒ3.5. Historically derived from the original 1925 50mm ƒ3.5 Elmax lens, which was an acronym of "(E)rnst", "(L)ieca" and "Professor (Max) Berek", designer of the original lenses. Later that year the 50mm ƒ3.5 Elmar superceded the Elmax, which was discontinued due to its complexity and high cost of manufacture.

Leica ElmaritElmarit Refers - Maximum lens aperture — here ƒ2.8. The name is obviously derived from the earlier (and slower) "Elmar" designation. Mind you, not every ƒ2.8 lens is called an "Elmarit". The most obvious exception being the 50mm ƒ2.8 Elmar-M lens, which for nostalgic and marketing reasons has kept the original 1930's "Elmar" designation (the 50mm ƒ3.5 collapsible Elmar, manufactured 1930-59, was one of Leica's most famous and popular lenses).

Leica HektorHektor -maximum lens aperture — usually ƒ2.5. The name was apparently taken from the name of lens designer Professor Max Berek's dog(!).

Leica LogoLeica A compound word derived from "Leitz" and "camera". Apparently they were going to use "LECA", but a French camera manufacturer already used a similar name, so they inserted an 'i' to prevent any confusion or trademark disputes.  Brief overviews of the company's history can be found here and here. If you were wondering why people would still want to use Leica cameras at all, especially in this digital day & age

Leica M LogoM (As in "M3", "M6", "M7" etc.) - "Messucher", which is German for "Viewfinder". The "3" in M3 was chosen because of the three bright line finders for the 50, 90 and 135 mm lenses. Later the numbers of the M cameras were more or less chosen to follow each other. Actually, the correct translation should really be "Rangefinder". "Viewfinder" (or "finder") is in fact the second part of the word, "Sucher". Meίsucher". It is always correctly written with the "ί". There are technically not three "s", rather the "ί" and one "s" because it is a word constructed by the combining of two precise words. Correction — since August 1st 1998, we have a new spelling in Germany. You now have to use three "s" instead of the "ί" plus "s". On the German Leica Website it now says Messsucher(!) The spelling is valid in Germany except for schools in Schleswig Hostein and writers at the Frankfurter Allgemeine Zeitung (FAZ), which means there's a lot of confusion now. Noctilux Refers to the maximum lens aperture — here ƒ1.0. "Nocti" for nocturnal, "lux" for light.

Leica RFRF - Range Finder - the mechano-optical mechanism which allows M Leicas to focus. Alternative meaning - RF is also shorthand for Hexar RF, Konica's motorized "M-lens-compatible" rangefinder camera released in 2000.

Summar - (or a story of name development)
The 1933 lens 50mm f2.0 Summar: It started out as Summar (f2.0), then the Summitar (f2.0 in 1939), then the Summarex (f1.5 in 1948), then the Summaron (35mm f.2.8 in 1948, then later f2.0, f3.5 and f5.6 lenses), then the Summarit (f1.5 in 1949 and used again for the 40mm f2.4 on the Leica Minilux in 1995, then again for the 35mm, 50mm, 75mm and 90mm Summarit f2.5 in 2007) then the Summicron (f2.0 in 1953 for the collabsible 50mm) and finally the Summilux (50mm f1.4 in 1959). ORIGIN of Summar is unknown.

Leica SummaritSummarit - Maximum lens aperture - here ƒ1.5. Presumably the name is a derivative of the root "Summicron" name in the same way "Elmarit" was derived from the slower "Elmar".

Leica SummicronSummicron Maximum lens aperture - here ƒ2.0. There are many guesses how this name came about, a popular one eing that the "summi" came from "summit" (summit means the highest point of a hill or mountain; the highest attainable level of achievement) while the "cron" came from "chroma" (ie. for color). Not so: The name (Summi)cron was used because the lens used Crown glass for the first time, which Leitz bought from Chance Brothers in England. The first batch of lenses were named Summikron (Crown = Krone in Deutsch). The Summi(cron) is a development from the orignal Summar (the 50mm f2.0 lens anno 1933)

Leica SummiluxSummilux - Maximum lens aperture - here ƒ1.4. "Summi" for "summit of performance" (same root as "Summicron"), with "lux" added for "light" (ie. enhanced light gathering abilities).

Leica TeleytTelyt Lens nomenclature - short-hand for "telephoto lens" (tele- is a combining form, meaning to or at a distance and used in names of instruments for operating over long distances : telemeter. ORIGIN: from Greek t?le- ‘far off.’


Leica TTLTTL - Through The Lens light metering, usually WRT the flash metering capabilities built into the R6.2, R8, R9, M7 & M6TTL cameras. Cameras featuring through-the-lens (TTL) exposure metering and including hand-held meters aimed directly at a scene measure the average mirrored intensity of light which yields dependable exposures for scenes containing average distribution of contrast and brightness. Subjects containing extreme contrast or incredibly bright or areas dominated by darkness need additional exposure.

Leica VulcaniteVulcanite The black rubberized, textured material used to cover Leica camera bodies prior to the 1980s. It was actually made of vulcanized rubber (hence the name) and remains much loved by professionals because of its solid, sure grip, Eventually moisture and dampness cause the material to deteriorate. Moisture , from bad storage or a humid environment , penetrates beneath the vulcanite and oxidizes the aluminium in the surface of the shell of the camera. This powdery , white oxide separates the adhesive holding the vulcanite tightly to the shell. Vulcanite , at room temperature , is brittle , like an ice-cream wafer . Consequently , when an area of vulcanite has separated from the body , it is easily snagged on a finger-nail , or just the pressure of the hand will crack the , already weakened covering.

Leica VFVF - View Finder — the eyepiece and associated optics you look through in a camera. The Leica Viewfinder Magnifier M 1.25x magnifies the viewfinder image by one quarter and the Leica Viewfinder Magnifier M 1.4x by two fifths. They provide a major aide in framing the subject at focal lengths above 50 mm. The viewfinder 1.25x is recommended for focal lengths of 50 mm or more and the viewfinder 1.4x for focal lengths of 75 mm or more. By magnifying the rangefinder images, it greatly enhances focusing accuracy, especially when shooting at telephoto focal lengths. The 1.4 x viewfinder magnifier turns into magnification of 1x (0.95x with M8 Models); this combination allows comfortable viewing of the subject with both eyes. The viewfinders are simply screwed into the viewfinder ocular of the Leica M. A small chain attached to the Leica M's carrying strap eyelet prevents it from being lost or damaged. A leather pouch is supplied for safekeeping when it's not attached.

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