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Looney 11 rule

Looney 11 rule 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 Looney 11 rule rather than just read about it. In short: In lunar photography, the Looney 11 rule (also known as the Looney f/11 rule) is a method of estimating correct exposures without a light meter. For daylight photography, there is a similar rule called the Sunny 16 rule.

Looney 11 rule — main illustration
Looney 11 rule — illustration

Key takeaways

  • Looney 11 rule belongs to science; place it in that map before memorising details.
  • Learn the definition first, then one example that makes the definition concrete.
  • Connect Looney 11 rule to a quantity you can measure, compute or draw — that is where exam questions come from.
  • Reproduce the core statement of Looney 11 rule from memory before moving on to harder problems.

Reference excerpt

In lunar photography, the Looney 11 rule (also known as the Looney f/11 rule) is a method of estimating correct exposures without a light meter. For daylight photography, there is a similar rule called the Sunny 16 rule. The basic rule is: "For astronomical photos of the Moon's surface, set aperture to f/11 and shutter speed to the [reciprocal of the] ISO film speed [or ISO setting]."

With ISO 100, the photographer should set the shutter speed to 1/100 or 1/125 second. (On some cameras, 1/125 second is the available setting nearest to 1/100 second.) With ISO 200, set it to 1/200 or 1/250 second. With ISO 400, set it to 1/400 or 1/500 second. As with other light readings, shutter speed can be changed as long as the f-number is altered to compensate, e.g. 1/250 second at f/8 gives equivalent exposure to 1/125 second at f/11. Generally, the adjustment is done such that for each step in aperture increase (i.e., decreasing the f-number), the exposure time has to be halved (or equivalently, the shutter speed doubled), and vice versa. This follows the more general rule derived from the mathematical relationship between aperture and exposure time—within reasonable ranges, exposure is proportional to the square of the aperture ratio and proportional to exposure time; thus, to maintain a constant level of exposure, a change in aperture by a factor c requires a change in exposure time by a factor 1/c2 and vice versa. Steps in aperture correspond to a factor close to the square root of two, so the above rule. The intensity of visible sunlight striking the surface of the Moon is essentially the same as at the surface of the Earth. The albedo of the Moon's surface material is lower (darker) than that of the Earth's surface, and the Looney 11 rule increases exposure by one stop versus the Sunny 16 rule.

See also Astrophotography Night photography Sunny 16 rule

References

External links Lunar Photography Exposure Guide

Illustrations

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Worked examples

Example 1 — a first encounter with Looney 11 rule

Start with the simplest possible case. Write down what Looney 11 rule 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 Looney 11 rule 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 Looney 11 rule 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 Looney 11 rule

In research
Looney 11 rule 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 Looney 11 rule 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
Looney 11 rule is common in secondary-school and first-year university syllabi. It links to neighbouring topics Photographic techniques, Rules of thumb, so understanding it makes those chapters shorter.
In everyday life
Look for Looney 11 rule 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 Looney 11 rule in 20 minutes

  1. Read the reference excerpt below once, without taking notes.
  2. Close the page and write down what Looney 11 rule means in your own words.
  3. Compare your version with the excerpt and mark what you missed.
  4. Work through the three examples above with pen and paper.
  5. Explain Looney 11 rule out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Looney 11 rule in simple terms?

In lunar photography, the Looney 11 rule (also known as the Looney f/11 rule) is a method of estimating correct exposures without a light meter. For daylight photography, there is a similar rule called the Sunny 16 rule.

Why does Looney 11 rule 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 Looney 11 rule?

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 Looney 11 rule.

Tags

  • Photographic techniques
  • Rules of thumb

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