生成AIに​おける​焦点距離の​比較

{
  "概要": "木漏れ日を浴びて、カメラに向かって満面の笑みを浮かべる若い女性",
  "被写体": {
    "年齢": "20代前半",
    "性別": "女性",
    "表情": "目が三日月形になるほどの屈託のない笑顔、白い歯を見せて笑っている",
    "視線": "カメラ目線",
    "顔の向き・姿勢": "体はやや斜め、顔をカメラ側に向けて首を少し傾けている、リラックスした自然な立ち姿",
    "肌": "明るく自然な肌、夕日を受けて頬や額がほんのり暖色に輝いている",
    "髪型": {
      "色": "ダークブラウン",
      "長さ": "肩につくくらいのミディアムヘア",
      "スタイル": "レイヤーの入った軽いくせ毛風、毛先が外にふんわり跳ねる、顔まわりに流れる前髪",
      "質感": "風になびいたような無造作でラフな動き、逆光で髪の輪郭が光る"
    },
    "服装": {
      "トップス": "白い無地の半袖Tシャツ、ゆったりしたオーバーサイズ気味のシルエット、薄手のコットン素材",
      "ディテール": "Tシャツに葉の影がまだら模様に落ちている"
    },
    "雰囲気": "無邪気、自然体、ノスタルジック、夏の夕方の穏やかさ"
  },
  "ライティング": {
    "光源": "夕方のゴールデンアワーの低い太陽光、画面左側から差し込む",
    "効果": "木漏れ日による斑の光と影が顔・髪・服に落ちる、暖かいハイライト"
  },
  "構図": {
    "フレーミング": "腰から上、縦長構図で人物を中央やや左寄りに配置",
    "アングル": "目線の高さ、少し離れた距離から"
  },
  "スタイル": "フィルム写真風、ややソフトで粒状感のある質感、暖色寄りのレトロな色味、フォトリアル",
  "ネガティブプロンプト": "硬い表情、強すぎるメイク、過度なレタッチ、不自然な肌、歪んだ顔、崩れた手、文字、ウォーターマーク"
}

ベース画像を参照画像として添付し、共通部分に焦点距離ごとの追加部分をつなげて入力した。

共通部分

Use the attached photo as the reference for the woman: same face, smile, wavy dark hair, white T-shirt. She wears light blue denim jeans and stands upright, facing the camera, arms relaxed at her sides.

Scene: she stands in a sunny clearing at the edge of a pine forest, warm late-afternoon light. The tall pine trunks and foliage are about 10 m behind her.

The camera is on a tripod about 20 m away from her, at her neck height, perfectly level, pointing straight at her. The camera, the woman and the forest NEVER move between shots. Only the focal length changes, so each shot looks like a center crop of the same scene: she is always at the horizontal center of the frame, and the relative size of her and the trees stays the same. Full-frame 35mm equivalent, aperture fixed at f/2.8, photorealistic, 16:9.

18mm

Shot at 18mm ultra-wide. She appears very small, her full body only about 7% of the image height, standing in the middle of a wide landscape: the whole clearing, grass in the foreground, the forest edge and plenty of sky. Everything in sharp focus.

28mm

Shot at 28mm wide-angle. She appears small, her full body about 11% of the image height. Wide view of the clearing, the forest edge and sky. Everything in sharp focus.

35mm

Shot at 35mm. Her full body is about 14% of the image height. The clearing and the line of pine trees behind her fill most of the frame, some sky at the top. Everything in sharp focus.

50mm

Shot at 50mm. Her full body is about 20% of the image height, clearly visible. Several pine trunks behind her, a little sky at the top. Background almost sharp.

80mm

Shot at 80mm. Her full body is about one third of the image height, with space around her. A few pine trunks and foliage behind her, little or no sky. Background slightly soft.

150mm

Shot at 150mm telephoto. Her full body, head to feet, fills about 60% of the image height. Behind her, only a few large tree trunks and foliage. Background softly blurred.

300mm

Shot at 300mm telephoto. Framed from the top of her head to mid-thigh. The background is one or two large tree trunks and foliage. Strong, creamy bokeh.

600mm

Shot at 600mm super-telephoto. Tight head-and-shoulders framing, similar to the attached reference. The background is a small, highly magnified patch of a trunk and leaves. Very heavy bokeh, background melted into soft green and golden blur.

ベース画像を参照画像として添付し、共通部分に焦点距離ごとの追加部分をつなげて入力した。

共通部分

Use the attached photo as the reference. The woman and the forest stay in exactly the same place; only the camera moves. The camera moves closer to or farther from her along a straight line at her eye level, and the focal length changes so that her face stays exactly the same size in the frame.

Keep the same woman exactly: same face, smile, wavy dark hair, white T-shirt, pose. Keep the same framing as the reference: chest-up, centered, camera at eye level, looking straight at her (no low angle, no high angle). Her face occupies about 11% of the image width, and her eyes are about 28% from the top of the image, exactly as in the reference.

Same warm late-afternoon sunlight in a pine forest. Full-frame 35mm equivalent, aperture fixed at f/2.8, photorealistic, 16:9.

18mm

Shot at 18mm ultra-wide, camera only about 0.5 m from her face. Because the camera is very close, the background appears very wide and far away: many thin trees on both sides, lots of sky through the canopy, forest floor visible. Trees look small and recede with strong perspective. Background almost fully in focus. Slight natural close-range perspective on her face and shoulders.

28mm

Shot at 28mm wide-angle, camera about 0.8 m from her. Wide background: several rows of trees and visible sky. Trees look fairly small and distant behind her. Background mostly sharp, only slightly soft.

35mm

Shot at 35mm, camera about 1 m from her. Moderately wide background: several tree trunks on both sides, some sky through the canopy. Trees look a little smaller and farther away than in the reference. Background slightly soft, trunk and leaf details still recognizable.

50mm

Shot at 50mm, camera about 1.5 m from her, same as the reference. Natural field of view: a few tree trunks on each side, a little sky at the top. Gentle, soft bokeh.

80mm

Shot at 80mm, camera about 2.4 m away from her. Narrower background: a few tree trunks behind her, little sky. Background appears closer and larger than in the reference. Moderate, smooth bokeh. Her face must NOT be larger than in the reference.

150mm

Shot at 150mm telephoto, camera about 4.5 m away from her. Only two or three large tree trunks and foliage fill the background, no sky. Background looks compressed and close behind her. Strong, creamy bokeh.

300mm

Shot at 300mm telephoto, camera about 9 m away from her. The background is a magnified section of foliage and one blurred trunk. Strong compression, the background feels like a wall right behind her. Very heavy bokeh, shapes dissolve into soft color.

600mm

Shot at 600mm super-telephoto, camera about 18 m away from her. The background is just a tiny, highly magnified patch of leaves and light. Extreme compression, background completely melted into smooth green and golden blur with large bokeh balls. Her face must NOT be larger than in the reference.