General[edit | edit source]

There are a significant number of lenses produced from the 1940s through the 1970s that are measurably radioactive. Main source of radioactivity is the use of thorium oxide (up to 30% by weight) as a component of the glass used in the lens elements. Thorium oxide has a crystalline structural similar to calcium fluoride (fluorite). Like fluorite, its optical properties of high refractivity and low dispersion allows lens designers to minimize chromatic aberration and use lenses of lower curvature, which are less expensive to produce. Despite statements to the contrary, lenses containing lanthanum are not appreciably radioactive - lanthanum is only 1/10,000th as radioactive as thorium. Radioactivity in lanthanum containing lenses is due to the intentional inclusion of thorium in the optical glass mix. The presence of thorium can sometimes, depending on the mixture of other elements in the lens, cause moderate to severe browning of the lens elements. Other common misconceptions hold that it is the coatings of these lenses which are radioactive and brown over time, and that the browning occurs in the balsam between cemented elements. It is the glass itself that contains the radioactive ThO2, and the browning therein is caused by the radiation-induced formation of color centers in the glass matrix.

Radiation Levels[edit | edit source]

Typical radiation levels can approach 10 mR/hr (100 μSv/h) as measured at the lens element's surface, decreasing substantially with distance; at a distance of 3 ft. (.9 m.) the radiation level is difficult to detect over typical background levels. For reference, a typical chest x-ray consists of about about 10 mR, a round-trip cross country airline flight exposes a passenger to 5 mR, and a full set of dental x-rays exposes the patient to 10 mR to 40mR. A study carried out by the Physics department of Sweden's Royal Institute of Technology estimates that total exposure to a professional photographer using a typical thoriated lens would amount to only 0.2% yearly allowable exposure to the eye and 0.17% to the whole body under the conservative standards of the Swedish Radiation Protection Authority.

Most smaller lenses with thorium elements pose a negligible risk to human health. However, thoriated glass eyepieces are significantly more dangerous. They can give a very large alpha and beta particle dose to the cornea of the eye, potentially causing cataracts and other problems. Normally these particles are stopped by skin, but the surface of the eye can be quickly damaged by them, and at close range, the dose can be very high.

Kodak Lenses[edit | edit source]

By far the most prolific known producer of radioactive lenses was Eastman Kodak. From the 1940s through the 1960s, substantial numbers of amateur cameras were produced and sold with thoriated (containing thorium oxide) lenses, including some of the Pony, Signet, and high end Instamatic (e.g. 800 and 814, but not 100 or 124) cameras. In addition, many professional level Ektar lenses from this era contain thorium. Perhaps the most famous radioactive lenses of all were the Kodak Aero-Ektars.

Curiously, in his notable book, A History Of The Photographic Lens, Rudolf Kingslake (head of the Eastman Kodak lens design department 1937-1968), makes only a single passing comment on the possible use of thorium in Kodak lenses.

Lenses with elements made of radioisotope-containing glass[edit | edit source]

Some lenses of the 1960s, such as early Minolta Rokkor lenses, have elements to made of glass formulas which include small traces of radioactive rare-earth elements. Sometimes this incidental radioactivity causes a significant browning of these lens elements. Some users of such lenses reported in camera blogs that they reduced the browning by exposing these lenses to the ultraviolet rays of the sun. The procedure requires several days of sunny weather to have a positive effect.

The effective diminishment of radiation-induced browning by exposure to sunlight has also been reported for some lenses with thorium glass elements, for example for the Nikkor 35mm f/1.4 lens and the Asahi Super Takumar 50mm f/1.4 lens. Several users have also reported that exposure to UV light from artificial sources, including fluorescent bulbs and UV-emitting LEDs is an even more effective method for reducing the appearance of browning.

Tested lenses[edit | edit source]

Lenses Tested Radioactive (by the creator of this page)[edit | edit source]

Lenses Tested Radioactive (elsewhere, or by contributors to this page)[edit | edit source]

  • Rodenstock XR-Heligon f/0.75 50mm: 5µS/h in 10 cm from front lens. Note: this lens was listed as non-radioactive. It might be that my sample was activated during usage in the X-Ray machine.
  • Argus Cintagon 50mm f/2.8
  • Agfa Color Solinar 2.8/50 (serial S51644): ~70cpm at the front
  • Agfa Solinar 50mm f/2.8 (Agfa Karat 36, front element group, serial S01812): 385CPM/2.4 uSv/h (front), ~100CPM/0.7 uSv/h (rear)
  • Bell & Howell Director Series (Model 1208?) XL Super 8 movie camera; Zoom Lens f: 1.2 \ F: 9-22.5 mm
  • Canon FL 50/1.4 (#15324) Up to 770 cpm at the rear lens. (very early version)
  • Canon FL 50/1.8 I (#58233): Up to 450 cpm / 26 µSv/h at the back lens, up to 7 cpm / 0.4 µSv/h behind camera or at the lens barrel. (early version with graphic hyperfocal distance scale) 
  • Canon FL 58/1.2 (#25516, #44528): Up to 180 cpm / 10 µSv/h at the back lens, up to 30 cpm / 1.7 µSv/h behind camera or at the lens barrel. YouTube
  • Canon FD 17mm f/4
  • Canon FD 35mm f/2.0 (versions from the early 1970's - concave front element)
  • Canon FD 50mm f/1.2 L (Early versions)
  • Canon FD 55mm f/1.2 S.S.C. Aspherical (Measured at 46532 CPM @ front element; S.S.C non-Aspherical is not radioactive) YouTube
  • Canon (SUPER-CANOMATIC LENS) R 50mm 1:1.8 No.78xxx YouTube
  • Carl Zeiss Jena Pancolar 55mm f1.4 (measured at 2360 nSv/h)
  • Carl Zeiss Jena Pancolar 50mm f1.8 "Zebra" (1964-67, up to serial number 8552600)
  • Carl Zeiss Planar 80mm f/2.8 (Rolleiflex 2.8D, taking lens: rear element measured at 0.12-0.18 uSv/h, serial 1242942)
  • Carl Zeiss Jena Biometar 80mm f2.8 "Zebra" "(Only P6 mount version )
  • Carl Zeiss Jena Flektogon 50mm f4 "Zebra" "(Only P6 mount version ) YouTube
  • Carl Zeiss Jena Prakticar 50mm f1.4 (1st version with engravings around the outer side of barrel)
  • Carl Zeiss Tessar 80mm f/2.8 (old silver Hasselblad version
  • Enna München Lithagon 1:3.5 35mm (M42) (
  • Focal (Kmart store brand) 35mm f/2.8
  • Fujica Fujinon 19mm f/3.5 EBC (Arkku at
  • Fujica Fujinon 35mm f/1.9 EBC (Arkku at
  • Fujica Fujinon 50mm f/1.4 non-EBC early style = non-uniformly segmented focusing ring (measured at 35137 CPM @ back element)
  • Fujica Fujinon 50mm f/1.4 EBC early style = non-uniformly segmented focusing ring YouTube (unspecified EBC or not)
  • Fujica Fujinon 100mm f/2.8 EBC (Arkku at
  • Fujica Fujinon 400mm f/4.5 EBC (Arkku at
  • Fujica Fujinon 600mm f/5.6 EBC (Arkku at
  • GAF Anscomatic 38mm f/2.8 (GAF Anscomatic 726 camera)
  • Heinz Kilfitt 40mm f/2.8 Makro-Kilar (all variants)
  • Heinz Kilfitt 90mm f/2.8 Makro Kilar (all variants)
  • Industar 61 L/Z MC is NOT radioactive, as the myth says (L is for Lanthanum. Only 0,089 % of total naturally found Lanthanum (La-138) isotope is radioactive, and even it has half-life of 105 billion years).
  • Kodak Aero-Ektars (various models) YouTube
  • Kodak Ektanon 4-inch Projection Lens f/3.5
  • Kodak Instamatic M24/26 Super 8 Camera YouTube
  • Kodak Ektar 80mm f/2.8 (for Hasselblad 1600F and 1000F, made 1948-1950)
  • Kodak Ektar 135mm f/3.5 (for Hasselblad 1600F and 1000F, made 1949)
  • Konica Hexanon AR 50mm f1.4 (smallest aperture 16; green AE marking)
  • Konica Hexanon 57mm f1.2 YouTube
  • Konica Hexanon 21mm f4 SN 7029XXX, primarily thorium and thorium decay products
  • Leica 50mm f/2 Collapsible Summicron YouTube
  • Leitz Wetzlar Summicron 5cm f2 (M39)
  • Mamiya/Sekor 55mm f/1.4 (m42, chrome+black, flat rear element) (Measured by specialists, 25th april 2014 @ Poissy, France: from 5 to 10 µSV/h by direct touch & 1720 CPM).
  • Mamiya/Sekor 58mm f/1.7 (M42 version) - 1.19 µSV/h (
  • Mamiya/Sekor SX 55mm f/1.8 6,8 µSV/h
  • Minolta MC W. Rokkor-SI 1:2.5 28mm (early variants)
  • Minolta MC Rokkor-PG 1:1.2 58mm (early variants only; SN 2571225 and later should be non-radioactive)
  • Minolta MC Rokkor 1:1.7 85mm (the earliest variant of the MC line)
  • Mitakon (Zhongyi) 50mm f0.95 Ver I Speedmaster (4 Lanthanum optic elements)
  • Mitakon (Zhongyi) 50mm f0.95 Ver II Dark Knight(1 Lanthanum optic element) - This lens has actually been tested by myself for beta & gamma radiation but has not been found to emit any detectable quantity. Please provide evidence of the contrary or remove this lens from list of radioactive ones. Reading somewhere that a lens may contain elements that could be radioactive is not enough to include it in the list.
  • Nikkor 35mm f/1.4 (early variant with thorium glass elements)
  • Olympus Zuiko MC Macro 20mm f/3.5 (
  • Olympus Zuiko Auto-S 1:1,2/55 mm (first version with thorium glass elements)
  • Olympus Zuiko Auto-S 1:1,4/50 mm (only first version "Silvernose" is Radioactive) YouTube
  • Olympus M-System G.Zuiko Auto-W 28mm F3.5 (early model) (
  • Olympus Zuiko Pen F 1:1.8/38mm (rear element, measured at approx. 7.5µSV/h or 26 µSv/h)  
  • Olympus Zuiko Pen F 1:1.4/40mm (rear element) 
  • Porst Color Reflex MC Auto 1:1.2/55mm (only a specific version? another copy reported as non-radioactive) #000670 - 37µSv/h
  • Porst Color Reflex MC Auto 1:1.2/55mm (f22 version-Tomioka serial until 00xxxx. #000543-10µSv/h #000543
  • Rikenon AUTO 55mm f/1.4 (22937 CPM rear element
  • Schneider Repro-Claron (
  • Schneider Kreuznach Retina-Xenon C 50mm f/2.8 (Kodak Retina IIc front lens, serial 3962395): measured at ~140CPM/.95 uSv/h
  •  Schneider Xenotar 80mm 2.8 (Rolleiflex 2.8C,1954) - 2 µSV/h on front element surface, 0.4 at 10cm, negligible at 20cm.
  • Schneider 135mm f/3.5 Xenotar (
  • SMC Pentax 50mm f/1.4 (original "K line") YouTube 
  • SMC Takumar 20mm f/4.5 (
  • SMC Takumar 35mm f/2.0 (Asahi Optical Co.)
  • Super Takumar 35mm f/2.0 (Asahi Optical Co.)
  • Super Multi Coated Takumar 50mm f/1.4 (Asahi Optical Co.) (both knurled and rubber focus ring grip versions) YouTube 
  • Super Takumar 50mm f/1.4 (All 7-element variants contain Thorium, no 8-element variants contain thorium)
    • Contrary to common belief, the early 8-element Super Takumar too is radioactive: Besides the lens shown here, I have tested 2 others for beta & gamma particles, getting readings at the back of up to about 1.2-1.35 µSv/h and at the front of about 0.2 µSv/h (against a background radiation of about 0.14 µSv/h). All 3 lenses have been verified to be of the 8 elements type: besides having all external characteristics, I serviced them, so I could count the elements. The radiactive elements are those at the back, not at the front. The good news is that all radiation from the rear is effectively stopped by a digital camera back (e.g. Sony Alpha 7RII). This is unfortunately not the case for the much more radioactive 7-element lenses.
    • This article is about Alpha radiation from Lanthanum or Thorium, not about Beta or Gamma radiation [False. This article is about all radiation types]. Yours may test positive for other types of radiation, but that doesn't mean that they all do [Nonsense. It's impossible to test all copies of a lens. If you test 3 copies & find them all radioactive, it's sensible to conclude the lens is radioactive]. Several other collectors have detected zero radiation of any kind from their examples, please do not over-generalize [Who are these 'collectors' and where is the evidence for these claims? This page should contain only statement supported by evidence]
    • My 8 elements is radioactive too. Video here
  • Super Takumar 50mm f/1.4 (Some 8-element variants, SN1554826) - Video test link here #1554826
  • Macro Takumar 50mm f4.0 early 1:1 version (serial 790115), rear element approx 58 µSv/h)
  • SMC Macro Takumar 50mm f/4.0 (
  • Super Takumar 55mm f/1.8 (Asahi Optical Co.)  (After approx. SN 1.5 million) Youtube
  • Super-Multi-Coated Takumar 55mm f/1.8 (Asahi Opt. Co.) (rear element, 8-10µSV/h)
  • Asahi Super Takumar 55mm f/1.8 (After approx. SN 1.5 million) -- (Serial 3199041 this is actually radioactive
  • SMC Takumar 55mm f/1.8 (Asahi Optical Co.) YouTube YouTube (not all)
  • Super Takumar 55mm f/2.0 (Asahi Optical Co.) YouTube
  • SMC Takumar 55mm f/2.0 (Asahi Optical Co.)
  • Super-Multi-Coated Takumar 85mm f1.8 (serial 5888634, front element only, not measurable at the back)
  • SMC Takumar 85mm f/1.8 (Asahi Optical Co.)
  • Soligor 35mm f/2.8 (serial 17000xxx) YouTube
  • Super Takumar 6x7 105mm f2.4 (Asahi Optical Co.)
  • Steinheil Auto-Quinon 55mm f/1.9 KE mount
  • Tele-Takumar 6.3 300mm (Asahi Optical Co.)
  • Topcor RE GN 50/1.4 (Lanthanum glass [source? Lanthanum or Thorium?]) YouTube
  • Topcon UV Topcor 50mm f/2 (Measured at 283nSv/h)
  • Yashinon-DX 28mm f/2.8 (Yashica) (Measured at 210 nSv/h)
  • Yashinon-DS 50mm f/1.4 (Yashica) (Measured at 680 nSv/h)
  • Yashinon-DS 50mm f/1.7 (Yashica) (Measured at 762 nSv/h)
  • Yashinon-DX 50mm f/1.4  (Yashica) (Measured at 1359 nSv/h)
  • Yashinon-DX 50mm f/1.8 (Yashica) YouTube
  • Yashinon-DS-M 50mm f/1.4 (Yashica) (Measured at 572 nSv/h)
  • Yashinon-DS-M 50mm f/1.7 (Yashica) (Measured at 798 nSv/hYouTube
  • Yashinon-DS-M 55mm f/1.2 (Yashica) (Measured at 1056 nSv/h)
  • Yashinon-ML 50mm f/1.7 (Yashica) YouTube (likely only the older design with 'YASHICA LENS ML 50mm 1:1.7 YASHICA MADE IN JAPAN' writings is radioactive.First version is in fact a DS-M 50mm f/1.7)
  • Yashinon 55mm f1.2 (Tomioka) (also branded as Cosinon, Chinon, Tominon, Tomioka or RevuenonMeasured at 981 nSv/h)
  • Ultragon 115mm f/5.5 (measured at 1.5μSv/h :
  • Vivitar Series 1 28mm f1.9 
  • Voigtlander 50mm Nokton Prominent
  • Voigtlander 15cm Apo-Lanthar (measured at 16μSv/h :
  • Voigtlander 21cm Apo-Lanthar (measured at 27μSv/h :
  • Voigtlander 30cm Apo-Lanthar (measured at 35μSv/h :
  • Voigtlander Zoomar 36-82mm f2.8 (measured at 3.1 μSv/h, serial 5033439)
  • Wollensak Raptar 28-75mm f2.3 YouTube
  • Zenitar-M 50mm f1.7 (Lanthanum glass)

Lenses Tested non-Radioactive (by contributors to this page)[edit | edit source]

Vintage lenses that could have been radioactive, but turned out not to be. A bit of good news!

  • Asahi Pentax-M 28mm f3.5 SMC Shift lens (serial 5144203)
  • Asahi smc Pentax-M 35mm f/2.8 (serial 6381843)
  • Asahi smc Pentax-K 50mm f/1.2 (serial 1451004)
  • Asahi Pentax-M 50mm f1.4 SMC Youtube
  • Asahi smc Pentax-M 50mm f/1.7 (serial 2596025, 2650094)
  • Asahi Pentax-M 50mm f2 SMC (serial 4286229)
  • Asahi Auto Takumar 55mm f2.2 (serial 641779)
  • Asahi Auto Takumar 85mm f1.8 - aperture ring at the front, spring-operated auto aperture (serial 412250)
  • Asahi Super-Takumar 55mm F2 (Early version) Youtube
  • Asahi Super Takumar 135mm f3.5 (serial 3088850)
  • Asahi Super Multi Coated Takumar 135mm f3.5 (serial 4568738)
  • Asahi smc Pentax-M 135mm f/3.5 (serial 6429171)
  • Canon FL 35mm F2.5 (serial 78xxx)
  • Canon FL 50mm F1.4 (serial 168xxx)
  • Canon FL 55mm F1.2 Youtube
  • Canon FD 28mm f2.8 S.C. chrome mount ring (serial 233953)
  • Canon 50mm f1.8 Leica Screw Mount, late model, chrome-and-black (serial 256884)
  • Carl Zeiss Sonnar 85mm f/2.8 ("Made in West Germany", Rollei QBM, serial 555345)
  • EBC Fujinon 50mm f/1.4 (late version: diamond-texture, rubber focus ring, serial 537963). Warning: Other samples may be highly radioactive!
  • Helios 44M 58mm f2.0 (serial 8077187)
  • Helios 44M-4 58mm f2.0 (serial 8990138)
  • Helios 44M-6 58mm f2.0 (serial 92621308)
  • Hoya HMC Wide-Auto 24mm f/2.8 (serial 211453, also RMC Tokina etc.)
  • Industar 28mm f/2.8
  • Konica Hexanon 135mm f/3.5 (serial 7322086)
  • Mamiya Sekor 55mm f/4.5 (C330 TLR, serials 74382/74610)
  • Mamiya Sekor 65mm f/3.5 (C330 TLR, serial 5790310, no second S/N)
  • Mamiya Sekor 80mm f/2.8 (C330 TLR, brown/yellowish coating, serials 672606/672341)
  • Mamiya Sekor Super 180mm f/4.5 (C330 TLR, serials 84462/85060)
  • Minolta MD Rokkor-X 50mm f/1.4
  • Mitakon Zhongyi 50mm f0.95 II 'Speedmaster' (serial 001525)
  • Olympus OM-System Zuiko Auto-S 50mm F1.4 (Late version, serial 1,15X,XXX) Youtube
  • Pentacon 135mm f/2.8 (Meyer Orestor Preset aperture non-MC version, serial 8477438)
  • Petri 55mm f/1.8 CC Auto (serial 691631)
  • Ricoh Color Rikenon 40mm f/2.8 (Rikoh 500GX, serial , could be slightly radioactive, but too low to be measured at my sample)
  • Ricoh Rikenon 400mm f/6.3 (serial 10443)
  • Rodenstock Heligon 50mm f/2 (Kodak Retina II, serial 2052276)
  • Rodenstock XR-Heligon f/0.75 50mm (serial 9723511). Another sample was measured to be radioactive (see above),
  • Rollei HFT-Planar 50mm f/1.8 (made by Rollei Singapore, early/metal version, serial 1078508)
  • Rollei SL-Xenon 50mm f/1.8 (Schneider-Kreuznach, serial 11 870 983)
  • Rollei SL-Angulon 35mm f/2.8 (Schneider-Kreuznach, serial 12 620 084)
  • MC Rubinar makro 500mm f/5.6 (Russian mirror tele lens, serial 080007)
  • Schneider Kreuznach Retina-Xenar 50mm f/3.5 (Kodak Retina Ia, serial 2216414)
  • Schneider Kreuznach Retina-Xenar C 50mm f/2.8 (Kodak Retina Ib, serial 4832242)
  • Schneider Kreuznach Retina-Xenon 50mm f/2.0 (Kodak Retina II, serial 1982005)
  • Schneider Kreuznach Retina-Xenon C 50mm f/2.0 (Kodak Retina IIIC, serial 5347221). Other apterture version (f/2.8) is radioactive (see above)
  • Tokina Wide-Auto (also applies to early Vivitar/Soligor auto wide: knurled metal focus ring) 35mm f/2.8 (serial 708205)
  • Vivitar Close Focusing Auto Zoom 75-205mm f/3.8 (early Kiron made version, two-ring zoom, serial 22616531)
  • Yashinon DX 45mm f1.4 (fixed lens on the Yashica 1C, Lynx 14-E rangefinder camera)
  • Zeiss Jena Flektogon Auto 35mm f2.4 (serial 74736)
  • Zeiss Jena Flektogon 35mm f2.8 Zebra version (serial 9060041)
  • Zeiss Jena Pancolar 50mm f1.8 "Zebra" (serial 9093379)

Links/Sources[edit | edit source]

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