The Asahi Optical Company (later Pentax) made history in 1964 by releasing a remarkable 50mm f/1.4 normal lens. This original Super-Takumar 50mm f/1.4 had eight optical elements in six groups – an unusually complex design for a standard lens at the time. Japanese engineers had deliberately pushed the envelope: their goal was to build a “Planar-killer” that could rival the best German optics of the day. In fact, Asahi’s engineers added a cemented doublet of curved elements to correct spherical and chromatic aberrations beyond what a typical 6- or 7-element Gauss design could achieve. The result was a lens with very high performance, but also very high manufacturing cost – so high that Asahi lost money on each copy it sold. This first-generation 8-element Takumar was sold briefly (about 1964–66) as a premium product. Its legend grew quickly: reviewers and press lauded its sharpness and “3-D” rendering, and Pentax marketing (and enthusiasts) started calling it a “Zeiss-killer”, meaning it could out-perform the famous Carl Zeiss Planar 50mm f/1.4 of 1963. As one reviewer notes, once Asahi earned that reputation, the company quietly replaced the costly 8-element model with a simpler 7-element version to protect its bottom line.
Vintage lens collection including an Asahi Super-Takumar 50mm f/1.4 (8-element version, bottom left) alongside other classic 50 mm lenses.
Origins and “Zeiss-Killer” Ambition
In the post‑war era, Pentax (then Asahi Optical Co.) rapidly built a reputation for outstanding cameras and lenses. By the early 1960s, European companies like Zeiss and Leica still led the high-end lens market. Asahi’s goal was simple: prove that a small Japanese company could make world-class glass. To that end, the new Super-Takumar 50/1.4 was engineered with no compromises. It shared features with only the most advanced lenses of the era. As one repair specialist notes, the 8-element Takumar was an “ambitious project” and a “masterpiece” given Asahi’s limited resources. They even worked within the narrow M42 screw mount used by Pentax cameras – a challenging constraint for very fast lenses. In short, the 8-element Super-Takumar was Pentax’s answer to the Zeiss Planar 50/1.4, aiming to match or exceed its optical pedigree.
This ambition did not go unnoticed. Early reviews and word-of-mouth singled out the Takumar’s unprecedented sharpness and rendering at f/1.4. The Japanese press and importers touted it as a “Planar-killer”, and among photographers it quickly earned the informal nickname “Zeiss Killer.” In essence, it was priced and praised as a 50/1.4 that could beat its German rival. In practice the differences were subtle, but the marketing stuck. One PentaxForums historian summarizes the story neatly: “It’s said that it was made to compete with the Carl Zeiss Planar 50mm f/1.4… This was meant as a Planar-killer and once its crown had been awarded by the press the simplified 7/6 version was quietly ushered in”. (In other words, Asahi won the publicity battle but found the lens too expensive to continue in large numbers.)
The first Takumar 50mm f/1.4 was a niche, short-lived lens – sold only in small quantities (around 1964–66). It was offered only as a factory-shipped lens with early Spotmatic SLRs, not sold standalone. Collectors later found that the 8-element version was mostly built during the first batch of Spotmatics, making it quite rare. Because each sold at a loss, Asahi soon revised the design, dropping an element and simplifying the optical formula. The result was a 7-element “second model” of Super-Takumar 50/1.4 (and later Super-Multi-Coated and SMC versions) from about 1967 onward. But the “original Takumar” retained a mystique among enthusiasts.
Optical Design and Build (8 Elements)
The 8-element Super-Takumar is a Double-Gauss-derived design (similar in concept to Zeiss and Leica 50mm f/1.4 lenses) but with an extra element to push the performance. Specifically, it has a cemented triplet in the center (three elements glued together) with strongly curved surfaces. This complicated triplet is very difficult to make, which drove up cost and gave the lens its bright amber coating hue. Indeed, many surviving copies have a noticeable yellowish tint – partly from the original coating, partly from age. (Important note: this original 8-element Takumar uses non-radioactive glass; the amber color is solely from its coating, not thorium, as explained below.)
In practice the lens is praised for sharpness and contrast. At f/1.4 it is often described as slightly soft with some spherical aberration and veiling flare, but stopping down dramatically improves acuity. By f/5.6–f/8 it becomes exceptionally sharp – some reviewers say almost “too honest” (very detailed) for portrait use. Its six-blade diaphragm renders a smooth, slightly octagonal bokeh. The out-of-focus highlight rendition is buttery, although not as creamy as a modern multi-coated 50mm. Some photographers love the shallow depth and luminous highlight glow at f/1.4; others find it less predictable (flatter in the center, more dreamy at the edges). Chromatic aberration and coma are visible wide-open on high-contrast edges, but these are normal for a f/1.4 lens of this vintage. Coatings are single-layer, so flare can be pronounced if a bright source enters the frame, but creative photographers have embraced the starbursts and swirls it can produce.
Physically, the lens is modestly sized and well-built: about 245 grams of mostly metal construction. Focusing is fully manual via a finely knurled ring with about 180° of rotation, moving the optical block for a minimum focus of roughly 0.45 m. There is a simple A/M (Auto/Manual) switch for the aperture lever on the mount, and a little pin which couples to a camera’s stop-down mechanism for auto-exposure metering. The aperture ring clicks through f/1.4, f/2, f/2.8, and stops in half-stop increments (early copies even had hard stops at every 1/2 stop). An unusual detail: early barrels used an orange “lollipop” marker in the depth-of-field scale, which later changed to a trapezoid or “diamond” symbol in 1964–65, but this cosmetic quirk is hard to notice at a glance. In general the 8-element Takumar feels very much like classic Japanese lenses of the era: solid but light by modern standards, with smooth focus and firm click-stops on the aperture.
Telling the 8-Element Apart from the 7-Element
Because the later 7-element Super-Takumar 50mm f/1.4 became much more common, collectors and buyers often ask how to distinguish it from the scarce 8-element original. Several clear identifiers exist:
- Depth-of-field (IR) mark: The infrared index marker (a small red line) lies differently. On the 8-element version, the IR mark is placed to the right of the numeral “4” on the depth-of-field scale. On the 7-element versions, it sits to the left, between the “4” and “8” marks. (This is one of the easiest visual cues: just look at the small red line near the 4 on the barrel.)
- Rear element shape: The rear lens element protrudes slightly outward on the 8-element lens. On the 7-element, the rear glass is more recessed behind the mount. In other words, if you invert the lens and look at the mount, the front surface of the 8-element’s last glass bulges a bit more than on the 7-element. Some enthusiasts say “if the rear element is curved (convex) it’s 8-element; if it’s flat it’s 7-element”.
- A/M switch and markings: The early 8-element Takumar uses a stop-down lever marked simply “A–M”, whereas later lenses (including all 7-element models) often used “Auto/Man” or similar wording. The 8-element’s mark is usually stamped on the lever itself at the rear.
- Aperture ring dot: On an 8-element lens, there is no dot above the “2” on the aperture ring. Some later 7-element copies have a small white dot or line there. This is subtle, but consistent: if you see a dot over f/2, you can be sure it’s a post‑8-element model.
- Serial/part numbers: The serial numbers overlap a bit, but ranges differ. Known data (from enthusiasts) suggests 8-element copies have serials roughly 7,660,24 through 1,581,354, while 7-element copies run from about 1,554,929 upward to 4,648,289. Also, inside the mount on the A/M lever some stamping differs: the 8-element (first model) typically shows product code “35800”, whereas the 7-element (second/third models) use “37800/37801/37802”. In practice, checking serials can help if you have data on range or a camera with that info.
- Label and branding: Early 8-element lenses are officially labeled “Super-Takumar” on the front ring, often with a red square “R” mark (on very earliest copies). The later 7-element lenses (and Multi-Coated variants) often say “Super-Multi-Coated Takumar” or “SMC Takumar” instead. On the original 8-element, the front rim engraving reads exactly “Super-Takumar 1:1.4 / 50mm” (sometimes without the “Super-”), whereas from 1967 onward the new models added the coating designation.
Putting these together lets a collector be confident: e.g. an early barrel showing A/M lever stamped “35800”, IR mark right of 4, and a slightly bulging rear element is surely the sought-after 8-element “Zeiss-killer” lens.
Thorium and the “Radioactive” Takumar
A famous footnote to the Takumar story is radioactivity. The 8-element Takumar itself uses non-radioactive glass (as mentioned above), but its successor did not. When Asahi redesigned the lens into a 7-element formula, they used some thorium-containing high-index glass in the rear elements (like many 1960s fast lenses). Thorium oxide (a rare-earth element) was added to increase the glass’s refractive index without excessive dispersion. This let the new version retain excellent optics in a simpler layout. The catch is that thorium is naturally slightly radioactive. Over years of exposure, the thorium glass slowly discolors (turns yellow or brown) and emits small amounts of radiation.
Why thorium? High-index glass was very useful for designers. According to radiation-history experts, adding thorium to lens glass (often 10–30% by weight) allowed a higher refractive index (above 1.6) while keeping dispersion low. That meant lenses could be made thinner or with simpler element counts without sacrificing image quality. Many classic lenses of the 1950s–’70s (e.g. the Nikkor 58mm f/1.2, early Leitz lenses, etc.) used thorium for the same reason. Asahi’s 7-element Takumar 50/1.4 followed this trend.
Implications: Thorium-glass lenses develop an amber tint over time. Photographers often notice old 7-element Super-Takumars turn yellow or orange in the rear elements. This is purely from the thorium glass oxidizing internally and emitting radiation that discolors the glass. It slightly filters the light (losing a stop or two of transmission) and can mellow the lens’s color balance. In practice, digital shooters simply correct white balance or UV-clean the glass (exposing it to bright light slowly “bleaches” the tint). Image quality isn’t dramatically harmed beyond this light loss; sharpness remains good.
Health-wise, the radioactivity is extremely low. Official sources report that carrying a camera with a thoriated lens might expose you to only a few millirem per year – a tiny fraction of natural background radiation. (For perspective, a cross-country airplane flight gives you about 3 mrem in a few hours.) In fact, Pentax explicitly disallowed thorium glass in any eyepiece or viewfinder (where you’d put your eye very close), but in a lens you’re never in contact. Anecdotal tests confirm modern photographers need not worry about the slight radioactivity. As one comment put it, the dose from a Takumar lens is “the same amount of radiation one could absorb on a transcontinental flight”. In short, the “radioactive” label mostly matters to collectors; its practical effect is the yellowing and that little bit of extra care in restoring old samples.
Importantly: only the 7-element Takumars have thorium. The original 8-element Super-Takumar did not use it. Veteran lens blogger Richard Haw explicitly notes that his 8-element Takumar shows yellow tint only because of its coating, not because of thorium. And a Takumar collector on Flickr confirms “the older lens has 8 elements and is non-radioactive… the newer and much more common lens has 7 elements and is radioactive”. So if you find a bright yellow Super-Takumar, it’s almost certainly a later 7-element model (or one with radioactive thorium in the glass).
7-Element Successor: Performance and Legacy
After 1966, Asahi’s simplified 7-element design took over. It was also called Super-Takumar (and later Super-Multi-Coated and SMC Takumar as coatings improved), but inside it was a different formula. Thanks to better anti-reflection coatings (from 1970s lens technology), the 7-element Super-Multi-Coated Takumar often looked cooler and less contrasty than the amber-tinted 8-element. It was made in much larger numbers and at lower cost.
In terms of image quality, opinions vary among modern users. Some find the 8-element lens has a unique “character” wide open – a certain glow and 3‑D pop – that feels special. Others see little difference stopped down. One vintage-lens reviewer says he finds “both [8 and 7 element] perfectly good” and “don’t notice much difference” in actual shots. Another photostream commenter notes the 7-element can be softer wide open, though “adequate” even for fast shooting. In practice, both lenses deliver very pleasing images, especially on modern digital cameras where they can be corrected for aberrations in software. The older 8-element tends to be more coveted by collectors, partly for its rarity and partly for nostalgia. The 7-element (and its coated successors) have the advantage of multi-coating that reduces flare and boosts contrast, and they often fetch lower prices simply because they’re common.
Historically, the 8-element lens is more of a cult item – the original “Zeiss killer” that proved Pentax’s prowess. The 7-element lens is less of a legend but is still a fine performer and often considered a workhorse classic. Both share the same iconic name and focal length, but for vintage-takumar fans the difference is clear: the 8-element is the lost chapter of Pentax’s story, while the 7-element is the chapter that actually wrote itself into photographic history worldwide.
In summary, the original Asahi Super-Takumar 50mm f/1.4 8-element lens was born from Pentax’s ambitious goal to outperform Zeiss and Leica. It earned its “Zeiss Killer” nickname in the mid-1960s by matching or beating contemporary 50mm standards. Its legacy lives on: today’s photographers prize it for its smooth bokeh, sharpness, and the lore behind its creation. By understanding its design, how to identify it, and the context of its thorium elements, enthusiasts can fully appreciate why this humble 50mm has such a legendary status.
Sources: Vintage lens databases and forums, authoritative blog reviews, and user discussions were consulted to trace the history, design details, and quirks of this classic lens. Each fact above is backed by cited references for accuracy.