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Lens speed

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Subject: Hektor (lens), Canon EF portrait lenses, Canon EF 400mm lens, Nocticron, Sports photography
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Lens speed

A fast prime (fixed focal length) lens, the Canon 50mm f/1.4 (left), and a slower zoom lens, the Canon 18–55mm f/3.5–5.6 (right); this lens is faster at 18mm than it is at 55mm.

Lens speed refers to the maximum aperture diameter, or minimum f-number, of a photographic lens. A lens with a larger maximum aperture (that is, a smaller minimum f-number) is called a "fast lens" because it delivers more light intensity (illuminance) to the focal plane, achieving the same exposure with a faster shutter speed. It also needs to reduce interference from extraneous (light) noise i.e. lower the noise floor. A smaller maximum aperture (larger minimum f-number) is "slow" because it delivers less light intensity i.e. has a higher noise floor and requires a slower shutter speed.

A lens may be referred to as "fast" or "slow" depending on its maximum aperture compared to other lenses of similar focal length designed for a similar film format. Lens speed given by the minimum f-number, or alternatively maximum aperture diameter or maximum numerical aperture, is a useful quantitative way to compare similar lenses.

Lens speed is important in taking pictures in dim light, or with long telephoto lenses. For controlling depth of field, especially in portrait photography,[1] lens speed is a key variable in combination with other variables such as focal length and camera format size.

Lenses may also be referred to as being "faster" or "slower" than one another using this same method. A lens with a maximum aperture of

  • Just how fast is that lens? f-number doesn't directly determine focal-plane illuminance, due to light transmission losses.

External links

  1. ^ Waldren, Margaret (and others) Advanced Digital Photography 2004 Media Publishing
  2. ^ Long, Ben Complete Digital Photography 2004 Charles River Media
  3. ^ a b c Maiello, Agostino (January 2000). "L'OBIETTIVO PIU' LUMINOSO DEL MONDO". (in Italian). Nadir Magazine. Retrieved 28 September 2013. 
  4. ^ Zhang, Michael (Aug 6, 2013). /0.33: The Fastest Lens Ever Made?"f"Carl Zeiss Super-Q-Gigantar 40mm . Petapixel. Retrieved 28 September 2013. 
  5. ^ "Cosina Voigtänder — Nokton 17.5mm F0.95 Aspherical".  
  6. ^ a b c "Cosina Voigtänder - Nokton 25mm F0.95".  
  7. ^ /0.95 at B&H PhotofThe Voigtlander 17.5mm
  8. ^ /0.95 at B&H PhotofThe Voigtlander 25mm
  9. ^ /0.95 at B&H PhotofThe Voigtlander 42.5mm
  10. ^ "Leica offers World's fastest Aspherical lens".  
  11. ^ "NOKTOR – Ultra Fast Lenses". Retrieved 2010-05-26. 
  12. ^ " – Noktor 50mm f/0.95". Retrieved 2011-11-22. 
  13. ^ "USAF Lens Datasheets - Type 1 Aerial Reconnaissance". Retrieved 4 October 2013. 
  14. ^ Two Special Lenses for "Barry Lyndon", by Ed DiGiulio (President, Cinema Products Corp.), American Cinematographer
  15. ^ Lossau, Jürgen (2003). The Complete Catalogue Of Movie Cameras, Hamburg/Germany, atoll medien, p. 59, ISBN 3-9807235-3-4
  16. ^ "Science, Kern-Paillard advertisement" (PDF) 165. 


  • /0.73 f
  • /0.73 f
  • /0.75 f
  • /0.75 f
  • /0.75 f
  • /0.75 f
  • /0.75 f
  • /0.95 etc. f
  • /0.75 f
  • /0.77 f
  • /0.8 f
  • /0.85 f
  • /0.9 (Photographic lens made by Lenzar Optics Corp., Riviera Beach FL, f0.9–f8) f
  • /0.95 f
  • /1.0 f
  • /1.0 f
  • /1.0 f
  • /1.0 f
  • /1.0 f
  • /1.0 f
  • Mt Prospect 90mm f/1.0
  • /1.0 f

Very fast lenses used in x-ray machines:

  • Kern Switar 13mm f/0.9
  • Cinetor 'TELE-PHOTO' 37.5mm f/1.0
  • Walz 'TELEPHOTO' 37.5mm f/1.0
  • Amitar 'Telephoto' 38.1mm f/1.0
  • Rexer 'TELE' 38mm f/1.0
  • Manon 'Telephoto' 37.5mm f/1.0

Very fast lenses in D-mount for 8mm movie use on H8 cameras:

  • /0.7 f
  • /0.78 f
  • Apollo 25mm f/0.85
  • Ernitec 25mm f/0.85
  • /0.85 f
  • Tarcus 25mm f/0.85
  • [16]/0.9 built for NASA for Apollo Moon landingf
  • Ampex 'LE610 Television Lens' 25mm f/0.95
  • /0.95 (M1 was a consumer product, while M2 was aimed at the professional cine market) f
  • /1.1 f
  • /0.95 f
  • /0.95 Type M1 (original more common), and Type M2 (better corrected for aberrations and distortions, designed for NASA, very rare and hard to find) f
  • AstroScope 25mm f/0.95
  • Avenir 25mm f/0.95
  • Century 'Nighthawk' 25mm f/0.95
  • Carl Meyer 25mm f/0.95
  • Cinetar 25mm f/0.95
  • Goyo Optical 17mm, 25mm, and 50mm f/0.95
  • JML 25mm and 50mm f/0.95
  • Navitar 25mm and 50mm f/0.95
  • Navitron 25mm and 50mm f/0.95
  • /0.95 f
  • Senko 25mm and 50mm f/0.95
  • /0.95 f
  • Som Berthiot 'Cinor' 25mm and 50mm f/0.95
  • Tarcus 'I.T.V. Lens' 50mm f/0.95
  • Precise Optics 50mm f/0.95
  • /0.95 f
  • Yakumo 25mm and 50mm f/0.95
  • Zeika 'Nominar' 25mm f/0.95
  • Kaligar 'Nominar' 25mm f/0.95
  • Dallmeyer 25mm f/0.99 (1930)
  • Astro Berlin 25mm f/1.0
  • Astro Berlin 'Tachonar' 35mm and 75mm f/1.0
  • Carl Meyer 38mm f/1.0
  • RTH (Rank/Taylor Hobson) Monital 130mm f/1.0 made by SOPELEM in France

Many very fast lenses exist in C-mount (such as used by CCTVs), including:

  • [13]/0.38 Solid Schmidt Mirror lens. Designed for aerial reconnaissancef
  • /0.5 Mirror lens f
  • /0.6 f
  • /0.65 Mirror lens f
  • /0.67 f
  • /0.7f Limited production lens built for the NASA space program, used on 35mm movie cameras by Stanley Kubrick for some candlelit scenes in Barry Lyndon[14]
  • expedition) South Pole/0.7, 8 elements in 4 groups, limited produced in 1944 for Japanese Army. (In 1951 another three were produced, two of which were used on a f
  • /0.7 Reproduction lens, not for photography. f
  • /0.71 Reproduction lens, not for photography. f
  • /0.75 Reproduction lens, not for photography. f
  • /0.75 Full Frame aerial photography lens f
  • /0.75 Medium Format aerial photography lens f
  • /0.8 f
  • /0.85 f
  • /0.85 f
  • /0.85 f
  • /0.87 f
  • /0.87 Medium Format aerial photography lens f
  • /0.9 f
  • /0.9 Fastest Nikon lens ever made f
  • /0.92 T0.95, Fastest cinema lens made for 35mm interchangeable lens camera f
  • /0.95 Available in TV and Canon 7 Rangefinder Version f
  • /0.95 f
  • /0.95 Medium Format aerial photography lens f
  • Solarmax/1.0 Medium Format Fish-eye lens. Only 3 were ever made for the Canadian Government for aurora borealis research in the late 60s/early 70s. One of these lenses was used in the production of the IMAX movie f
  • /1.0 Leica M mount, discontinued and replaced 2008 with a new Noctilux, see above f
  • /1.0 for Canon autofocus SLR, now out of production f
  • /1.0 f
  • /1.0 Prototype lens for Nikkor-S Rangefinder camera f
  • /1.1 lens for Nikkor-S Rangefinder camera f
  • Noct-Nikkor 58mm f/1.2
  • /1.0 f
  • /1.0 Medium Format aerial photography lens f
  • /1.0 f
  • /1.0 f
  • [15] silent and sound camera series, fastest lens ever made in Super8, was originally advertised as facilitating "shooting at candlelight" in combination with 160-ASA films.Super 8mm/1.0 zoom lens, made 1975–1983 for the 310XL f

The following camera lenses are no longer in production as of 2010:

  • Mitakon 50mm and 35mm f/0.95

And as of 2014:

  • Handevision Ibelux 40mm f/0.85, Made for multiple camera mounts including Micro 4/3, Sony E-Mount and Fujifilm X-Mount
  • [7][6][5] mountMicro Four Thirds/0.95 Aspherical f
  • [8][6] mountMicro Four Thirds/0.95 f
  • [9][6] mountMicro Four Thirds/0.95 f
  • [10] to have ever reached mass production, with a MSRP of £6290 (approximately US$10,000).aspherical lens/0.95 ASPH announced on September 15, 2008, it is one of the fastest f
  • SLR Magic HyperPrime LM 50mm T0.95 (f/0.92)
  • [12]Micro Four Thirds system a fast CCTV lens design adapted for the [11]/0.95 'HyperPrime'f
  • SLR Magic 25mm T/0.95
  • SLR Magic 35mm T/0.95

Some of the fastest camera lenses in production as of 2011 were as follows:

List of ultrafast lenses

Since sin θ < 1, it follows that no lens can be faster than f/0.5 if it operates in air. Lenses can be made faster than this by requiring the film emulsion to be in physical contact with the rear element, thus eliminating the air gap between the lens and the emulsion.

This sets a limit close to f/1.0 to f/1.2 for most SRL mounts, whereas lenses for rangefinder and mirrorless cameras can be faster, as they can be brought closer to the image plane. Reproduction lenses incapable of infinity focus can have nominal f-numbers smaller than this limit, as the limit applies to the working f-number (the f-number corrected by the bellows factor), not to the nominal f-number. It should be noted that only the working f-number correctly assesses the light gathering power of the lens.

  • NAmax is the largest possible numerical aperture,
  • n is the index of refraction of the medium behind the lens, most often air where n = 1,
  • θ is the half-angle of the maximum cone of light that can reach the film or sensor.


N_\text{min} = \frac{1}{2\;\mathrm{NA}_\text{max}} = \frac{1}{2\,n \sin\theta}

Ultimately, the speed of a lens is limited by mechanical constraints of the camera system (shutter or mirror clearance, mount diameter). The smallest possible working f-number is

Maximum possible speed

[4][3]) the claimed speed and focal lengths were purely nominal and it wasn't usable for photography.darkroom condenser enlarger Made from various parts found around the factory (the lenses came from a [3].photokina/0.33 at f In 1966 in response to the trend [3] In the mid 60s there was something of a fad for fast lenses among the major manufacturers.

/1.4. f/1.4; see f/1.2 lens and an autofocus 85mm f/1.2 lenses, while Nikon makes a manual focus 50mm f/1.4 lens. These are not unusual lenses and are relatively inexpensive. Canon also makes autofocus 50mm and 85mm f As of 2012, Canon, Nikon, Pentax and Sony all make an autofocus 50mm

/1.4. f/2.0 are each 1 f-stop apart (2× as fast), as an f-stop corresponds to a factor of f/1.4, and f/1.0, f/0.7, f/0.5, f For scale, note that

/1.2f showing their large entrance pupils

Fast lenses


  • Fast lenses 1
    • Maximum possible speed 1.1
    • List of ultrafast lenses 1.2
  • References 2
  • External links 3

/1.4, were historically produced abundantly, and are thus sold relatively inexpensively on the used lens market. f Lens speed also tends to correlate with the price and/or quality of the lens. This is because lenses with larger maximum apertures require greater care with regard to design, precision of manufacture, special coatings and quality of glass. At wide apertures,

The fastest lenses in general production are f/1.2 or f/1.4, with more at f/1.8 and f/2.0, and many at f/2.8 or slower; f/1.0 is unusual, though sees some use, e.g. the discontinued Canon 50mm f/1.0, and highly unusual older examples of f/0.6, f/0.7, f/0.8, f/0.9 etc. exist, e.g. the Zeiss 50mm f/0.7 NASA Kubrick lenses adapted to old film cameras and modern DV cameras.

With 35mm cameras, the fastest lenses are typically in the "normal lens" range near 50mm. Longer telephoto designs and wide-angle retrofocus designs tend to be slower. Attaining maximum lens speed requires engineering tradeoffs, and as such, "prime" (fixed focal length) lenses are generally faster than zoom lenses, and modern manual-focus lenses are generally faster than their autofocus counterparts.[2]

/11." f The range of lenses considered "fast" has evolved to lower f-numbers over the years, due to advances in

/1.2, though both are fast lenses. f

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