Lens speed

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File:Lensspeed.jpg
A fast prime (fixed focal length) lens, the Canon 50mm <templatestyles src="F//styles.css" />f/1.4 (left), and a slower zoom lens, the Canon 18–55mm <templatestyles src="F//styles.css" />f/3.5–5.6 (right); this lens is faster at 18mm than it is at 55mm.

Lens speed is the maximum aperture diameter, or minimum f-number, of a photographic lens. A lens with a larger than average maximum aperture (that is, a smaller minimum f-number) is called a "fast lens" because it can achieve the same exposure as an average lens with a faster shutter speed. Conversely, a smaller maximum aperture (larger minimum f-number) is "slow" because it delivers less light intensity and requires a slower (longer) shutter speed.

A fast lens speed is desirable in taking pictures in dim light, for stability with long telephoto lenses, and for controlling depth of field and bokeh, especially in portrait photography,[1] as well as for sports photography and photojournalism.

Lenses may also be referred to as being "faster" or "slower" than one another; so an <templatestyles src="F//styles.css" />f/3.5 lens can be described as faster than an <templatestyles src="F//styles.css" />f/5.6 despite <templatestyles src="F//styles.css" />f/3.5 not generally being considered "fast" outright. What is considered fast largely depends on focal length, image diameter (i.e. format covered, such as APS, full frame, medium format), and in the case of zoom lenses, zoom factor.

Tradeoffs

File:Three Minolta 50 mm photographic lenses with different lens speeds of 3.5, 1.7, and 1.2.jpg
Three 50 mm prime lenses from Minolta with lens speed 3.5 (a macro photography lens, speed of less priority), 1.7 (standard), and 1.2 (large opening and high speed, typically expensive), showing the relation between entry lens diameter and lens speed.

Attaining maximum lens speed requires engineering tradeoffs, and as such, "prime" (fixed focal length) lenses are generally faster than zoom lenses.[2]

With 35mm film cameras and full-frame digital cameras, the fastest lenses are typically in the "normal lens" range near 50mm; here, there are several relatively inexpensive high-quality fast lenses available. For example, the Canon EF 50mm <templatestyles src="F//styles.css" />f/1.8 II or Nikon AF Nikkor 50mm <templatestyles src="F//styles.css" />f/1.8D are very inexpensive, but quite fast and optically well-regarded. Old fast manual focus lenses, such as the Nikkor-S(C) or Nikkor AI-S 50mm <templatestyles src="F//styles.css" />f/1.4, or Canon's FD and M39 counterparts, were historically produced abundantly, and are thus sold relatively inexpensively on the used lens market.

Especially outside of the "normal" focal length, 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, spherical aberration becomes more significant and must be corrected. Thus, faster telephoto and wide-angle retrofocus designs tend to be much more expensive.

A telecompressor, also known as a speed booster, may be used to increase the speed of a lens with a corresponding reduction to its focal length. For example, the Metabones 0.58x BMPCC speed booster may be combined with a <templatestyles src="F//styles.css" />f/1.2 lens to produce <templatestyles src="F//styles.css" />f/0.74.[3]

Fast lenses

While the fastest lenses in general production in the 2010s were <templatestyles src="F//styles.css" />f/1.2 or <templatestyles src="F//styles.css" />f/1.4, the 2020s have seen several <templatestyles src="F//styles.css" />f/0.95 lenses, see below.

What is considered "fast" has evolved to lower f-numbers over the years, due to advances in lens design, optical manufacturing, quality of glass, optical coatings, and the move toward smaller imaging formats. For example, the 1911 Encyclopædia Britannica states that "...[Lenses] are also sometimes classified according to their rapidity, as expressed by their effective apertures, into extra rapid, with apertures larger than <templatestyles src="F//styles.css" />f/6; rapid, with apertures from <templatestyles src="F//styles.css" />f/6 to <templatestyles src="F//styles.css" />f/8; slow, with apertures less than <templatestyles src="F//styles.css" />f/11" whilst today, <templatestyles src="F//styles.css" />f/6 would be deemed at the rather slow end.

File:Canon 85mm comparison (front).jpg
Canon 85mm <templatestyles src="F//styles.css" />f/1.8 and <templatestyles src="F//styles.css" />f/1.2 showing their large entrance pupils

For scale, note that <templatestyles src="F//styles.css" />f/0.5, <templatestyles src="F//styles.css" />f/0.7, <templatestyles src="F//styles.css" />f/1.0, <templatestyles src="F//styles.css" />f/1.4, and <templatestyles src="F//styles.css" />f/2.0 are each 1 f-stop apart (2× as fast), as an f-stop corresponds to a factor of the square root of 2, about 1.4. Thus around <templatestyles src="F//styles.css" />f/1.0, a change of 0.1 corresponds to about 1/4 of an f-stop (by linear approximation): <templatestyles src="F//styles.css" />f/1.0 is about 50% faster than <templatestyles src="F//styles.css" />f/1.2, which is about 50% faster than <templatestyles src="F//styles.css" />f/1.4.

since 2017Template:Dated maintenance category (articles)Script error: No such module "Check for unknown parameters"., Canon, Nikon, Pentax and Sony all make an autofocus 50mm <templatestyles src="F//styles.css" />f/1.4 lens. These are not unusual lenses and are relatively inexpensive. As of 2023, Canon also makes autofocus 50mm and 85mm <templatestyles src="F//styles.css" />f/1.2 lenses, while Nikon makes a manual focus 58mm <templatestyles src="F//styles.css" />f/0.95 lens and autofocus 50 and 85mm <templatestyles src="F//styles.css" />f/1.2 lenses; see Canon EF 50mm lenses and Canon EF 85mm lenses for details. Pentax makes a 50mm <templatestyles src="F//styles.css" />f/1.4 lens and 55mm <templatestyles src="F//styles.css" />f/1.4 lens for APS-C cameras; see Pentax lenses. Sony makes several 50mm <templatestyles src="F//styles.css" />f/1.4 lenses as well as a 50mm <templatestyles src="F//styles.css" />f/1.2.

The maximum exposure time for hand-held photography can be increased with an image stabilisation system. In 2014, Panasonic introduced the fastest lens with in-built stabilisation, the Leica Nocticron 42.5 mm f/1.2, which can even be operated with dual image stabilisation (Dual I.S.), provided that the camera body has an additional stabilising system at the image sensor.

In the mid 1960s, there was something of a fad for fast lenses among the major manufacturers.[4] In 1966, in response to the trend, Carl Zeiss displayed a prop lens christened the Super-Q-Gigantar 40mm <templatestyles src="F//styles.css" />f/0.33 at photokina.[4] Made from various parts found around the factory (the lenses came from a darkroom condenser enlarger), the claimed speed and focal lengths were purely nominal and it wasn't usable for photography.[4][5]

Maximum possible speed

Theoretically, the smallest f-number is 0 (or numerical aperture of 1), corresponding to a lens with an infinite entrance pupil diameter. In practice, that cannot be reached due to mechanical constraints of the camera system (shutter clearance, mount diameter). Even for systems that can be designed without significant constraints on lens size and image plane distance (e.g. microscopy and photolithography systems), the cost of going beyond a numerical aperture of 0.95 (f/0.164) is usually prohibitive.

In SLR camera systems, typical mount diameters are in the range of 44–54 mm, with flange distances around 45 mm. This limits the maximum possible f-number to <templatestyles src="F//styles.css" />f/1.0 to <templatestyles src="F//styles.css" />f/1.2, with rather strong vignetting towards the edges of the image. Flange distances are significantly smaller for rangefinder and mirrorless cameras (even below 20 mm), theoretically enabling designs down to something like f/0.7 or even faster. The chance of seeing such lenses designed for use with 35mm ("full-frame") cameras, digital or film, in practice will be slim, since their cost and weight are likely not competitive with respect to equivalent imaging solutions employing larger sensors.

List of ultrafast lenses

Some of the fastest camera lenses in production since 2021Template:Dated maintenance category (articles)Script error: No such module "Check for unknown parameters". were as follows:

File:Voigtlaender.Super.Nokton.29F0.8.jpg
Cosina Voigtländer Super Nokton 29 mm / 0.8
  • Cosina Voigtländer Super Nokton 29mm <templatestyles src="F//styles.css" />f/0.8 Micro Four Thirds mount[6][7]
  • Cosina Voigtländer Nokton 10.5mm, 17.5mm, 25mm, 42.5mm, 60mm <templatestyles src="F//styles.css" />f/0.95 for Micro Four Thirds mount [8]
  • Vantage One T1.0 Cine lenses from 17.5mm to 120mm (Super35mm Spherical Primes)
  • SLR Magic 25mm T/0.95
  • SLR Magic 35mm T/0.95
  • Laowa 18mm, 25mm, 33mm <templatestyles src="F//styles.css" />f/0.95 (T1.0) For Super35mm Frame sensor
  • Laowa 28mm, 35mm, 45mm <templatestyles src="F//styles.css" />f/0.95 (T1.0) For Full Frame sensor
  • Handevision Ibelux 40mm <templatestyles src="F//styles.css" />f/0.85 (made for Micro Four Thirds and various APS camera mounts, including Sony E-Mount and Fujifilm X-Mount)
  • Fujinon 43mm <templatestyles src="F//styles.css" />f/0.85 VRF43LMD (used in LAS 3000 biomolecular Imager)Script error: No such module "Unsubst".
  • Leica Noctilux-M 50mm <templatestyles src="F//styles.css" />f/0.95 ASPH (announced on September 15, 2008, then the fastest aspherical lens to have reached mass production; MSRP of £6290 or approximately US$10,000).[9]
  • Zhongyi Mitakon 50mm and 35mm <templatestyles src="F//styles.css" />f/0.95 in various optical versions and mounts, of which at least the 50mm for Leica M rangefinders has been found to in fact only be <templatestyles src="F//styles.css" />f/1.06![10]
  • Nikon Noct-Nikkor Z 58mm <templatestyles src="F//styles.css" />f/0.95

The following lenses are no longer in production since 2021Template:Dated maintenance category (articles)Script error: No such module "Check for unknown parameters".:

  • American Optical 81mm 3.259" <templatestyles src="F//styles.css" />f/0.38 Solid Schmidt Mirror lens (designed for aerial reconnaissance) [11]
  • GOI CV 20mm <templatestyles src="F//styles.css" />f/0.5 Mirror lens (2.9 mm image diameter, 1948; design and glass types used are well documented for anyone wanting to build their own
  • Signal Corps Engineering 33mm <templatestyles src="F//styles.css" />f/0.6[12]
  • GOI Iskra-3 72mm <templatestyles src="F//styles.css" />f/0.65 Mirror lens
  • Fujinon-IDEAX 125mm <templatestyles src="F//styles.css" />f/0.67 and/or <templatestyles src="F//styles.css" />f/0.85 (X-ray lens, two speeds quoted on front ring)[13]
  • Zeiss Planar 50mm <templatestyles src="F//styles.css" />f/0.7 (Limited 10-copies production for the NASA space program, later used on 35mm movie cameras by Stanley Kubrick for some candlelit scenes in Barry Lyndon)[14]
  • Tokyo Kogaku Similar 50mm <templatestyles src="F//styles.css" />f/0.7 (8 elements in 4 groups, limited production in 1944 for Japanese Army. In 1951, another three were produced, two of which were used on a South Pole expedition)
  • Kinoptik Lynxar 60mm <templatestyles src="F//styles.css" />f/0.7 (Reproduction lens, usable but not optimised for photography)
  • Wray 64mm <templatestyles src="F//styles.css" />f/0.71 (Reproduction lens, usable but not optimised for photography)
  • LOMO 60mm <templatestyles src="F//styles.css" />f/0.75 (Reproduction lens, usable but not optimised for photography)
  • Aerojet Delft Rayxar 105mm <templatestyles src="F//styles.css" />f/0.75 Full Frame aerial photography lensScript error: No such module "Unsubst".
  • Aerojet Delft Rayxar 150mm <templatestyles src="F//styles.css" />f/0.75 Medium Format aerial photography lensScript error: No such module "Unsubst".
  • Aerojet Delft Rayxar 250mm <templatestyles src="F//styles.css" />f/0.75 Large Format aerial photography lensScript error: No such module "Unsubst".
  • American Optical 43mm 1.715" <templatestyles src="F//styles.css" />f/0.8
  • JML Optical 64mm <templatestyles src="F//styles.css" />f/0.85
  • Leica Summar 75mm <templatestyles src="F//styles.css" />f/0.85 Reproduction lens, not for photography.
  • Leica Leitz-IR 150mm <templatestyles src="F//styles.css" />f/0.85 Reproduction lens, not for photography.
  • Farrand Super Farron 76mm <templatestyles src="F//styles.css" />f/0.87
  • Farrand Super Farron 150mm <templatestyles src="F//styles.css" />f/0.87 Medium Format aerial photography lens
  • Canon 50mm <templatestyles src="F//styles.css" />f/0.95 (made as a rangefinder-coupled version with proprietary external bayonet for Canon 7 rangefinders, and an uncoupled C-mount "TV" version)
  • Kiev Рекорд-4 (Rekord-4) 52mm <templatestyles src="F//styles.css" />f/0.9 (rangefinder lens, remained a prototype despite better resolution than the Canon 50mm<templatestyles src="F//styles.css" />f/0.95 rangefinder lens)[15]
  • Nikon TV-Nikkor 35mm <templatestyles src="F//styles.css" />f/0.9 (Fastest Nikon lens ever made; TV lens in M39 lens mount, 12.6 mm diameter image circle)[16]
  • Noktor 50mm <templatestyles src="F//styles.css" />f/0.95 (C-mount lens converted for mirrorless cameras; the actual C-mount lens is still being made as D.O. Industries Kowa Navitron, JML, Tarcus; Elgeet Navitar, SLRMagic Hyperprime, Senko, Yakumo; Goyo; Ernitec Super)
  • SLR Magic HyperPrime CINE and LM 50mm <templatestyles src="F//styles.css" />f/0.92 T0.95 (rangefinder lens, Erwin Puts measured it to be T1.12!Noctilux 0.95/50)
  • Astro Berlin 52mm <templatestyles src="F//styles.css" />f/0.95 (Super-35 Cine lens)
  • Leitz Perkin Elmer 4.5" 114mm <templatestyles src="F//styles.css" />f/0.95 T1 (aerial photography lens, 40mm image diameter, 1967)
  • Pacific Optical 25mm <templatestyles src="F//styles.css" />f/1.0 (Medium Format 150° Fish-eye lens, 55 mm image diameter; only 3 copies 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 Solarmax, one is presumed lost; the cost per piece was estimated at 250,000 USD)
  • Leica Noctilux-M 50mm <templatestyles src="F//styles.css" />f/1.0 (Leica M mount, 1976; discontinued and replaced 2008 with a new Noctilux, see above)
  • Canon EF 50mm <templatestyles src="F//styles.css" />f/1.0 L USM (for Canon EOS autofocus SLRs, announced 1987, released 1989, discontinued 2009)
  • Panavision 50mm <templatestyles src="F//styles.css" />f/1.0 (Super-35 cine lens)
  • Nikkor-O 50mm <templatestyles src="F//styles.css" />f/1.0 Prototype lens for Nikkor-S Rangefinder camera
  • Leica ELCAN 90mm <templatestyles src="F//styles.css" />f/1.0
  • Wild Heerbrugg Reconar 98mm <templatestyles src="F//styles.css" />f/1.0 Medium Format aerial photography lens
  • Kollmorgen 153mm <templatestyles src="F//styles.css" />f/1.0
  • Zeiss UR 250mm <templatestyles src="F//styles.css" />f/1.0
  • Canon 8.5–25.5mm <templatestyles src="F//styles.css" />f/1.0 zoom lens (made 1975–1983 for the 310XL Super 8mm silent and sound camera series, the fastest zoom lens ever made for Super8, originally advertised as facilitating "shooting at candlelight" in combination with 160-ASA films.)[17]
  • Baker-Nunn camera 500mm <templatestyles src="F//styles.css" />f/0.75 twelve used for tracking satellites[18]

Apart from those already mentioned, many very fast lenses exist in C-mount (as used by 16mm film cameras, CCTV, medical & scientific imaging systems), including:

  • Fujinon 50mm <templatestyles src="F//styles.css" />f/0.7
  • Canon 'TV-16' 25mm <templatestyles src="F//styles.css" />f/0.78
  • Fujinon YV2.7x2.9LR4A-SA 2.9-8mm <templatestyles src="F//styles.css" />f/0.95
  • Apollo 25mm <templatestyles src="F//styles.css" />f/0.85
  • Computar 8mm <templatestyles src="F//styles.css" />f/0.8 (6.4 x 4.8 mm image)
  • Ernitec 25mm <templatestyles src="F//styles.css" />f/0.85
  • Fujinon 25mm <templatestyles src="F//styles.css" />f/0.85
  • Tarcus 25mm <templatestyles src="F//styles.css" />f/0.85
  • Kern Switar 18mm <templatestyles src="F//styles.css" />f/0.9 (built for NASA for the Apollo Moon landing)[19]
  • Ampex 'LE610 Television Lens' 25mm <templatestyles src="F//styles.css" />f/0.95
  • Angénieux 25mm <templatestyles src="F//styles.css" />f/0.95 Type 'M1' and 'M2' (M1 was the original, more common, consumer-grade product, while M2 was aimed at the professional cine market, with better correction for aberrations and distortions)
  • Angénieux 28mm <templatestyles src="F//styles.css" />f/0.95 Type 'M1' and 'M2' (for 16mm film)
  • Angénieux 35mm <templatestyles src="F//styles.css" />f/0.95
  • Angénieux 50mm <templatestyles src="F//styles.css" />f/0.95 Type 'M1' and 'M2'
  • AstroScope 25mm <templatestyles src="F//styles.css" />f/0.95
  • Avenir 25mm <templatestyles src="F//styles.css" />f/0.95
  • Century 'Nighthawk' 25mm <templatestyles src="F//styles.css" />f/0.95
  • Carl Meyer 25mm <templatestyles src="F//styles.css" />f/0.95
  • Cinetar 25mm <templatestyles src="F//styles.css" />f/0.95
  • Goyo Optical 17mm, 25mm, and 50mm <templatestyles src="F//styles.css" />f/0.95
  • JML 25mm and 50mm <templatestyles src="F//styles.css" />f/0.95
  • Navitar 25mm and 50mm <templatestyles src="F//styles.css" />f/0.95 (see also above entry to the Noktor)
  • Navitron 25mm and 50mm <templatestyles src="F//styles.css" />f/0.95 (see also above entry to the Noktor)
  • Schneider Kreuznach 'Xenon' 17mm, 25mm, and 50mm <templatestyles src="F//styles.css" />f/0.95
  • Senko 25mm and 50mm <templatestyles src="F//styles.css" />f/0.95 (see also above entry to the Noktor)
  • Soligor 'Super Elitar' 25mm <templatestyles src="F//styles.css" />f/0.95
  • Som Berthiot 'Cinor' 25mm and 50mm <templatestyles src="F//styles.css" />f/0.95
  • Tarcus 'I.T.V. Lens' 50mm <templatestyles src="F//styles.css" />f/0.95
  • Precise Optics 50mm <templatestyles src="F//styles.css" />f/0.95
  • Kowa 50mm <templatestyles src="F//styles.css" />f/0.95
  • Yakumo 25mm and 50mm <templatestyles src="F//styles.css" />f/0.95
  • Zeika 'Nominar' 25mm <templatestyles src="F//styles.css" />f/0.95
  • Kaligar 'Nominar' 25mm <templatestyles src="F//styles.css" />f/0.95
  • Dallmeyer 25mm <templatestyles src="F//styles.css" />f/0.99 (1930)
  • Astro Berlin 25mm <templatestyles src="F//styles.css" />f/1.0
  • Bausch & Lomb 29mm <templatestyles src="F//styles.css" />f/1.0
  • Astro Berlin 'Tachonar' 35mm and 75mm <templatestyles src="F//styles.css" />f/1.0
  • Carl Meyer Videostigmat 1.5" 38mm <templatestyles src="F//styles.css" />f/1.0 [20]
  • RTH (Rank/Taylor Hobson) Monital 130mm <templatestyles src="F//styles.css" />f/1.0 made by SOPELEM in France, Super35mm cine lens

Very fast lenses in D-mount for use in (Super-)8mm film and video (Hi)8 cameras:

  • Kern Switar 13mm <templatestyles src="F//styles.css" />f/0.9
  • Cinetor 'TELE-PHOTO' 37.5mm <templatestyles src="F//styles.css" />f/1.0
  • Walz 'TELEPHOTO' 37.5mm <templatestyles src="F//styles.css" />f/1.0
  • Amitar 'Telephoto' 38.1mm <templatestyles src="F//styles.css" />f/1.0
  • Rexer 'TELE' 38mm <templatestyles src="F//styles.css" />f/1.0
  • Manon 'Telephoto' 37.5mm <templatestyles src="F//styles.css" />f/1.0

Very fast lenses used in X-ray machines:

  • Zeiss R-Biotar 100mm <templatestyles src="F//styles.css" />f/0.73
  • LOMO 100mm <templatestyles src="F//styles.css" />f/0.73
  • Canon 50mm and 65mm <templatestyles src="F//styles.css" />f/0.75
  • Leitz 50mm and 65mm <templatestyles src="F//styles.css" />f/0.75
  • De Oude Delft Rayxar 50mm, 65mm and 105mm, and allegedly 150mmScript error: No such module "Unsubst". <templatestyles src="F//styles.css" />f/0.75
  • De Oude Delft Rayxar 90mm <templatestyles src="F//styles.css" />f/1.0
  • Astro-Berlin Tachon 65mm <templatestyles src="F//styles.css" />f/0.75
  • Rodenstock XR-Heligon 42mm and 50mm <templatestyles src="F//styles.css" />f/0.75
  • Rodenstock XR-Heligon 68mm f/1[21]
  • Kowa 42mm and 65mm <templatestyles src="F//styles.css" />f/0.75
  • Carl Zeiss Jena 50mm <templatestyles src="F//styles.css" />f/0.77
  • Kowa 55mm <templatestyles src="F//styles.css" />f/0.8
  • Zeiss R-Biotar 55mm <templatestyles src="F//styles.css" />f/0.85
  • Lenzar Optics 184.6mm <templatestyles src="F//styles.css" />f/0.9 (Photographic lens made by Lenzar Optics Corp., Riviera Beach FL, <templatestyles src="F//styles.css" />f/0.9–8)
  • Kowa 33.5mm <templatestyles src="F//styles.css" />f/0.95Script error: No such module "Unsubst".
  • Kowa 55mm <templatestyles src="F//styles.css" />f/1.0
  • Rodenstock Heligon 68mm <templatestyles src="F//styles.css" />f/1.0
  • Canon 65mm and 90mm <templatestyles src="F//styles.css" />f/1.0
  • Fuji 90mm <templatestyles src="F//styles.css" />f/1.0
  • Kowa 90mm <templatestyles src="F//styles.css" />f/1.0
  • Zeiss R-Biotar 125mm <templatestyles src="F//styles.css" />f/0.8

References

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  1. ↑ Waldren, Margaret (and others) Advanced Digital Photography 2004 Media Publishing
  2. ↑ Long, Ben Complete Digital Photography 2004 Charles River Media
  3. ↑ Script error: No such module "citation/CS1".
  4. ↑ a b c Script error: No such module "citation/CS1".
  5. ↑ Script error: No such module "citation/CS1".
  6. ↑ Script error: No such module "citation/CS1".
  7. ↑ Script error: No such module "citation/CS1".
  8. ↑ Script error: No such module "citation/CS1".
  9. ↑ Script error: No such module "citation/CS1".
  10. ↑ Script error: No such module "citation/CS1".
  11. ↑ Script error: No such module "citation/CS1".
  12. ↑ Script error: No such module "citation/CS1".
  13. ↑ Script error: No such module "citation/CS1".
  14. ↑ Two Special Lenses for "Barry Lyndon", by Ed DiGiulio (President, Cinema Products Corp.), American Cinematographer
  15. ↑ Script error: No such module "citation/CS1".
  16. ↑ Script error: No such module "citation/CS1".
  17. ↑ Lossau, Jürgen (2003). The Complete Catalogue Of Movie Cameras, Hamburg/Germany, atoll medien, p. 59, Template:ISBN
  18. ↑ Script error: No such module "citation/CS1".
  19. ↑ Script error: No such module "Citation/CS1".
  20. ↑ Script error: No such module "citation/CS1".
  21. ↑ Script error: No such module "citation/CS1".

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External links

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