"stop down" meaning in English

{
  "antonyms": [
    {
      "word": "stop up"
    }
  ],
  "forms": [
    {
      "form": "stops down",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "stopping down",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "stopped down",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "stopped down",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "stop down (third-person singular simple present stops down, present participle stopping down, simple past and past participle stopped down)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "English phrasal verbs with particle (down)",
          "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": "1982, Marvin J. Rosen, Introduction to photography: a self-directing approach, 2nd edition, page 71",
          "text": "The f/stops are arranged so that as you stop down, each stop allows half the amount of light to pass through as the stop before it did.",
          "type": "quotation"
        },
        {
          "ref": "2002 December 12, “Images from a blurred world”, in The Economist, retrieved 2009-04-03",
          "text": "To get an image with a larger “depth of field”—ie, where more of the distant objects as well as the nearer ones in a scene are in focus—the photographer must “stop down” the aperture of the lens, restricting the amount of light admitted.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "To decrease the aperture of a photographic lens, moving from an f/stop represented by a lower number to an f/stop represented by a higher number."
      ],
      "id": "en-stop_down-en-verb-o0YOgkZU",
      "links": [
        [
          "photography",
          "photography"
        ],
        [
          "decrease",
          "decrease"
        ],
        [
          "aperture",
          "aperture"
        ],
        [
          "photographic",
          "photographic"
        ],
        [
          "lens",
          "lens"
        ],
        [
          "f/stop",
          "f/stop"
        ]
      ],
      "raw_glosses": [
        "(photography) To decrease the aperture of a photographic lens, moving from an f/stop represented by a lower number to an f/stop represented by a higher number."
      ],
      "topics": [
        "arts",
        "hobbies",
        "lifestyle",
        "photography"
      ]
    }
  ],
  "word": "stop down"
}

{
  "antonyms": [
    {
      "word": "stop up"
    }
  ],
  "forms": [
    {
      "form": "stops down",
      "tags": [
        "present",
        "singular",
        "third-person"
      ]
    },
    {
      "form": "stopping down",
      "tags": [
        "participle",
        "present"
      ]
    },
    {
      "form": "stopped down",
      "tags": [
        "participle",
        "past"
      ]
    },
    {
      "form": "stopped down",
      "tags": [
        "past"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "*"
      },
      "expansion": "stop down (third-person singular simple present stops down, present participle stopping down, simple past and past participle stopped down)",
      "name": "en-verb"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "verb",
  "senses": [
    {
      "categories": [
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English phrasal verbs",
        "English phrasal verbs with particle (down)",
        "English terms with quotations",
        "English verbs",
        "en:Photography"
      ],
      "examples": [
        {
          "ref": "1982, Marvin J. Rosen, Introduction to photography: a self-directing approach, 2nd edition, page 71",
          "text": "The f/stops are arranged so that as you stop down, each stop allows half the amount of light to pass through as the stop before it did.",
          "type": "quotation"
        },
        {
          "ref": "2002 December 12, “Images from a blurred world”, in The Economist, retrieved 2009-04-03",
          "text": "To get an image with a larger “depth of field”—ie, where more of the distant objects as well as the nearer ones in a scene are in focus—the photographer must “stop down” the aperture of the lens, restricting the amount of light admitted.",
          "type": "quotation"
        }
      ],
      "glosses": [
        "To decrease the aperture of a photographic lens, moving from an f/stop represented by a lower number to an f/stop represented by a higher number."
      ],
      "links": [
        [
          "photography",
          "photography"
        ],
        [
          "decrease",
          "decrease"
        ],
        [
          "aperture",
          "aperture"
        ],
        [
          "photographic",
          "photographic"
        ],
        [
          "lens",
          "lens"
        ],
        [
          "f/stop",
          "f/stop"
        ]
      ],
      "raw_glosses": [
        "(photography) To decrease the aperture of a photographic lens, moving from an f/stop represented by a lower number to an f/stop represented by a higher number."
      ],
      "topics": [
        "arts",
        "hobbies",
        "lifestyle",
        "photography"
      ]
    }
  ],
  "word": "stop down"
}