"focusing screen" meaning in English

{
  "forms": [
    {
      "form": "focusing screens",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "focusing screen (plural focusing screens)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
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          "kind": "other",
          "name": "Entries with translation boxes",
          "parents": [],
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        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
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          "source": "w"
        },
        {
          "kind": "other",
          "name": "Terms with Polish translations",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "topical",
          "langcode": "en",
          "name": "Photography",
          "orig": "en:Photography",
          "parents": [
            "Art",
            "Human activity",
            "Media",
            "Culture",
            "Human behaviour",
            "Communication",
            "Society",
            "Human",
            "All topics",
            "Fundamental"
          ],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1993 July, Herbert Keppler, “SLR: Have manufacturers fouled up viewing screens for technological progress?”, in Popular Photography, volume 57, number 3, page 17:",
          "text": "Once the microgrid and split-image rangefinder became the major focusing controls, the focusing screen itself became a secondary or even tertiary focusing area and was/is generally ignored by many users.",
          "type": "quote"
        },
        {
          "ref": "2012, Ernst Wildi, The Medium Format Advantage, →ISBN, page 183:",
          "text": "You can always see the covered area on the focusing screen regardless what the subject distance might be or what close-up accessories are used.",
          "type": "quote"
        },
        {
          "ref": "2012, Jeffrey R. Charles, Practical Astrophotography, →ISBN:",
          "text": "This is because the reflex mirror in some SLR cameras is not quite long enough to provide full illumination of the entire focusing screen with the image from a telescope. Fortunately, such reduced illumination of the focusing screen will not affect your photograph.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A flat translucent material found in a system camera that allows the photographer to preview the framed image in a viewfinder."
      ],
      "id": "en-focusing_screen-en-noun-jN6u7zAh",
      "links": [
        [
          "photography",
          "photography"
        ],
        [
          "flat",
          "flat"
        ],
        [
          "translucent",
          "translucent"
        ],
        [
          "camera",
          "camera"
        ],
        [
          "photographer",
          "photographer"
        ],
        [
          "preview",
          "preview"
        ],
        [
          "viewfinder",
          "viewfinder"
        ]
      ],
      "raw_glosses": [
        "(photography) A flat translucent material found in a system camera that allows the photographer to preview the framed image in a viewfinder."
      ],
      "topics": [
        "arts",
        "hobbies",
        "lifestyle",
        "photography"
      ],
      "translations": [
        {
          "code": "pl",
          "lang": "Polish",
          "sense": "Translations",
          "tags": [
            "feminine"
          ],
          "word": "matówka"
        }
      ],
      "wikipedia": [
        "focusing screen"
      ]
    }
  ],
  "word": "focusing screen"
}

{
  "forms": [
    {
      "form": "focusing screens",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {},
      "expansion": "focusing screen (plural focusing screens)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Entries with translation boxes",
        "Pages with 1 entry",
        "Pages with entries",
        "Terms with Polish translations",
        "Translation table header lacks gloss",
        "en:Photography"
      ],
      "examples": [
        {
          "ref": "1993 July, Herbert Keppler, “SLR: Have manufacturers fouled up viewing screens for technological progress?”, in Popular Photography, volume 57, number 3, page 17:",
          "text": "Once the microgrid and split-image rangefinder became the major focusing controls, the focusing screen itself became a secondary or even tertiary focusing area and was/is generally ignored by many users.",
          "type": "quote"
        },
        {
          "ref": "2012, Ernst Wildi, The Medium Format Advantage, →ISBN, page 183:",
          "text": "You can always see the covered area on the focusing screen regardless what the subject distance might be or what close-up accessories are used.",
          "type": "quote"
        },
        {
          "ref": "2012, Jeffrey R. Charles, Practical Astrophotography, →ISBN:",
          "text": "This is because the reflex mirror in some SLR cameras is not quite long enough to provide full illumination of the entire focusing screen with the image from a telescope. Fortunately, such reduced illumination of the focusing screen will not affect your photograph.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A flat translucent material found in a system camera that allows the photographer to preview the framed image in a viewfinder."
      ],
      "links": [
        [
          "photography",
          "photography"
        ],
        [
          "flat",
          "flat"
        ],
        [
          "translucent",
          "translucent"
        ],
        [
          "camera",
          "camera"
        ],
        [
          "photographer",
          "photographer"
        ],
        [
          "preview",
          "preview"
        ],
        [
          "viewfinder",
          "viewfinder"
        ]
      ],
      "raw_glosses": [
        "(photography) A flat translucent material found in a system camera that allows the photographer to preview the framed image in a viewfinder."
      ],
      "topics": [
        "arts",
        "hobbies",
        "lifestyle",
        "photography"
      ],
      "wikipedia": [
        "focusing screen"
      ]
    }
  ],
  "translations": [
    {
      "code": "pl",
      "lang": "Polish",
      "sense": "Translations",
      "tags": [
        "feminine"
      ],
      "word": "matówka"
    }
  ],
  "word": "focusing screen"
}