science

Takumar

Takumar is a science topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Takumar rather than just read about it. In short: Takumar is the name that Asahi Optical gave to its lenses, notably but not exclusively those for its own SLR cameras. Named after the Japanese-American portrait painter, Takuma Kajiwara (梶原啄磨, Kajiwara Takuma), whose brother Kumao Kajiwara founded Asahi Optical.

Key takeaways

Takumar belongs to science; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Takumar to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Takumar from memory before moving on to harder problems.

Reference excerpt

Takumar is the name that Asahi Optical gave to its lenses, notably but not exclusively those for its own SLR cameras. Named after the Japanese-American portrait painter, Takuma Kajiwara (梶原啄磨, Kajiwara Takuma), whose brother Kumao Kajiwara founded Asahi Optical. The name adorned its lenses until 1975, when Asahi switched from the M42 screw mount to the bayonet K-mount. K-mount lenses were simply named "SMC Pentax". Some Takumar lenses were also made for the K-mount.

Details The Takumar designation was used on lenses designed for Asahi's 35 mm cameras, 6×7 cameras, and for other purposes too.

Takumar lenses were made in M37 screwmount for the original Asahiflex cameras and continued into the M42 period. Auto-Takumar lenses were a type of preset lens. The user selected an aperture then engaged a lever to energise the stopping-down mechanism. The camera would then trip this mechanism when the shutter was fired. Super-Takumar lenses featured an improved form of lens coating (to reduce flare) and a more sophisticated stopping-down mechanism. There was a switch on the lens to select "Auto" or "Manual" modes. In manual mode, the lens would always be in the selected aperture. In Auto mode, the lens would remain wide open (at maximum aperture) until a pin on the rear of the lens was pushed in. This pin would be automatically pushed in by the camera when the shutter was tripped. Super-Multi-Coated (later SMC) Takumar. These lenses introduced Asahi's lens multi-coating process (to further reduce reflections and flare). They also introduced a lug on the rear of the lens which moved with the aperture selected. When used with a camera body which could read the lug, this enabled the use of open-aperture metering. Examples of such cameras are Asahi's Spotmatic F and the ES/ESII. These SMC-Takumar M42 thread mount lenses included: 15/3.5 rectilinear ultra-wide angle, 17/4 full-frame fisheye, 20/4.5, 24/3.5, 28/3.5, 35/2, 35/2.8, 50/1.4, 50/4 macro, 55/1.8, 55/2, 85/1.8, 100/4 macro, 105/2.8, 120/2.8, 135/2.5, 135/3.5, 150/4, 200/4, 300/4, 400/5.6, 500/4.5, 1000/8. Pentax resurrected the Takumar name in the 1980s and 1990s for a budget line of zoom and prime lenses that lacked the Pentax "Super Multi-Coating" anti-reflective coating that reduces lens flare. These lenses are marked "Takumar (Bayonet)" or "Takumar-F" to distinguish them from the older screw-mount Takumar lenses. Non-Asahi cameras with Asahi lenses branded Takumar include the Suzuki Press Van and two versions of the Takane Mine Six.

Gallery

See also Nikkor Rokkor Fujinon Zuiko Yashinon Yashikor

References

(in Japanese) Asahi Camera editorial staff. Shōwa 10–40nen kōkoku ni miru kokusan kamera no rekishi (昭和10〜40年広告にみる国産カメラの歴史, Japanese camera history as seen in advertisements, 1935–1965). Tokyo: Asahi Shinbunsha, 1994. ISBN 4-02-330312-7.

External links

Comprehensive Pentax Screwmount (M42) Lens info User reviews of Takumar lenses at Pentaxforums.com

Illustrations

Worked examples

Example 1 — a first encounter with Takumar

Start with the simplest possible case. Write down what Takumar claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In science, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Takumar before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Takumar ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Takumar

In research: Takumar appears in science research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Takumar in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Takumar is common in secondary-school and first-year university syllabi. It links to neighbouring topics Japanese brands, Japanese inventions, Pentax lenses, so understanding it makes those chapters shorter.
In everyday life: Look for Takumar outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Takumar in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Takumar means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Takumar out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Takumar in simple terms?

Why does Takumar matter?

Because it connects several science ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Takumar?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Takumar.