defocus

low
UK/diːˈfəʊkəs/US/diːˈfoʊkəs/

technical, formal

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Definition

Meaning

To cause something (especially an optical system, like a lens, or attention) to lose sharpness or clarity; to move away from a point of focus.

To deliberately reduce concentration on a specific point, task, or idea, often to gain a broader perspective or to soften an effect.

Linguistics

Semantic Notes

Primarily a transitive verb, but can be used intransitively. Most common in technical fields like optics, photography, and physics, but has metaphorical extension in management and psychology.

Dialectal Variation

British vs American Usage

Differences

No significant differences in meaning or usage.

Connotations

Neutral and technical in both varieties.

Frequency

Equally low in general use, but standard in technical registers in both regions.

Vocabulary

Collocations

strong
defocus the lensdefocus the imagedefocus the beam
medium
slightly defocusdeliberately defocusdefocus the attention
weak
defocus the minddefocus the discussiondefocus the camera

Grammar

Valency Patterns

[NP] defocus [NP] (transitive)[NP] defocus (intransitive)

Vocabulary

Synonyms

Strong

obscuremake indistinct

Neutral

blursoft-focus

Weak

dimcloud

Vocabulary

Antonyms

focussharpenclarifyconcentrate

Phrases

Idioms & Phrases

  • None

Usage

Context Usage

Business

Rare; used metaphorically in strategy discussions: 'We need to defocus from micro-details and look at the broader market.'

Academic

Common in physics, engineering, and optics papers describing experimental setups.

Everyday

Very rare; limited to photography enthusiasts.

Technical

Standard term in optics, microscopy, photography, and laser physics.

Examples

By Part of Speech

verb

British English

  • You must defocus the telescope to observe the nebula's halo.
  • The debate began to defocus as more topics were introduced.

American English

  • Defocus the microscope slightly to see the phase contrast.
  • The manager warned the team not to defocus their efforts.

adverb

British English

  • The light shone defocusedly through the frosted glass. (rare)

American English

  • He stared defocusedly at the report, not taking anything in. (rare)

adjective

British English

  • The defocused background created a pleasing bokeh effect.
  • Her thoughts were defocused and scattered.

American English

  • A defocused laser beam can be dangerous.
  • He gave a defocused, rambling presentation.

Examples

By CEFR Level

A2
  • The photo is blurry because the camera is defocused.
B1
  • To get that soft background, you need to defocus the lens.
B2
  • The project began to fail when the team leader defocused and started pursuing unrelated goals.
C1
  • The researcher intentionally introduced a slight defocus to the electron beam to analyse the specimen's thickness variations.

Learning

Memory Aids

Mnemonic

DE-FOCUS: DE-tach from FOCUS.

Conceptual Metaphor

CLARITY IS SHARPNESS / LOSS OF CLARITY IS BLURRING

Watch out

Common Pitfalls

Translation Traps (for Russian speakers)

  • Avoid calquing as 'дефокусировать' in non-technical contexts; use 'расфокусировать' (technical) or 'терять концентрацию' (metaphorical).
  • Do not confuse with 'distract' (отвлекать) which implies an external agent.

Common Mistakes

  • Using 'defocus' as a primary synonym for 'distract'.
  • Incorrect preposition: 'defocus on' instead of 'defocus' (transitive) or 'defocus from'.

Practice

Quiz

Fill in the gap
In portrait photography, it is common to the background to make the subject stand out.
Multiple Choice

In a metaphorical sense, what does it mean to 'defocus'?

FAQ

Frequently Asked Questions

No, it is a low-frequency word primarily used in technical contexts like optics and photography.

Yes, but it's rare. The noun form 'defocus' (e.g., 'a slight defocus') is used in technical writing.

The direct opposite is 'focus' (verb) or 'bring into focus'.

Very rarely. It is mostly a technical term, though photography enthusiasts might use it.