science

Sync box

Sync box 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 Sync box rather than just read about it. In short: A sync box, also known as a phase adjuster in England, is a device designed to sync a film camera's shutter with TV or computer screens, otherwise thick, black roll bars appear on the video screen within the film image. Process A lot of problems when filming TV and computer screens are based on the different frame rates involved.

Key takeaways

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

Reference excerpt

A sync box, also known as a phase adjuster in England, is a device designed to sync a film camera's shutter with TV or computer screens, otherwise thick, black roll bars appear on the video screen within the film image.

Process A lot of problems when filming TV and computer screens are based on the different frame rates involved. The standard for film projection is 24 fps. In countries like the United States that use the NTSC system for television broadcast, the frame rate is 30 fps (actually 29.97). When the camera's shutter is not in sync with the NTSC monitor, thick, dark horizontal bands or bars will appear and drift across the screen. These are called "roll bars". A sync box with phase control is used to eliminate the roll bars. Shooting at 24 fps with a 144° camera shutter will reduce the size of the roll bars to very thin lines. At this shutter angle, using a sync box with the camera can stop the thin roll bars from moving. Phase control allows the camera operator to place the thin roll bars at any point in the frame. The choice of placement generally comes down to two options: Having two lines, one at the top third and one at the bottom third of the display, or only one line right across the center.

Solutions without sync boxes In certain cases, filmmakers found ways of filming television screens without the use of sync boxes. Documented examples include:

Mark Irwin, director of photography on Videodrome (1983), did not have access to a sync box during that film for shooting many scenes involving TV screens. He used a camera with a fixed shutter speed to reduce roll bars to very thin lines in that film, thus making them imperceptible. One of the technical innovations introduced in Star Trek II: The Wrath of Khan was the use of 24-frame video playback though specially designed TV sets and videotape players. This allows for the filming of video screens without black bars or flickering, thus negating the need for a sync box. The system was designed by Hal Landaker at The Burbank Studios.

References

Annotations

Footnotes

Bibliography Malkiewicz, Kris; Mullen, M. David (June 21, 2005). "8: Special Shooting Techniques". Cinematography: Third Edition. Simon and Schuster.

External links Filming Computer Monitors on the Cinematography Mailing List

Worked examples

Example 1 — a first encounter with Sync box

Start with the simplest possible case. Write down what Sync box 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 Sync box 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 Sync box 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 Sync box

In research: Sync box 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 Sync box 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: Sync box is common in secondary-school and first-year university syllabi. It links to neighbouring topics Cinematography, Filmmaking, Television technology, so understanding it makes those chapters shorter.
In everyday life: Look for Sync box 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 Sync box in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Sync box 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 Sync box out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Sync box in simple terms?

Why does Sync box 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 Sync box?

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 Sync box.