blender-cameras

Blender Cameras

Set up cameras with the same decisions a real cinematographer makes: focal length for feel, f-stop for focus, composition for storytelling.

Focal length cheat sheet

Length	Feel	Use
14–24mm	Very wide, distorted	Architecture, claustrophobic interiors, exaggerated perspective
28–35mm	Wide, "documentary"	Establishing shots, environments
50mm	Neutral (≈ human eye)	Default storytelling
85mm	Short telephoto	Portraits, character close-ups (flattering)
100–135mm	Telephoto	Hero product shots, isolated subjects
200mm+	Long tele	Wildlife, surveillance look, heavy compression

Quick rule: 85mm for intimacy, 24mm for spectacle, 50mm for neutral.

Aperture / f-stop

f-stop	DoF	Use
f/1.2–2.0	Razor thin	Hero portraits, dreamy
f/2.8	Shallow	Standard portrait
f/4	Moderate	Two subjects in frame
f/5.6–8	Medium-deep	Group portraits, environments
f/11+	Very deep	Landscape, "everything sharp"

Recipes

Recipe 0 — Bbox-aware hero camera (preferred for orchestrator chains)

Use this when you have a specific subject. Computes the subject's bounding box, places camera at a distance that fits the subject in ~80% of the frame vertically, and aims via Track-To.

import bpy, math
from mathutils import Vector

# Choose subject — all meshes named GEO-* by default, or pass a specific list
subject_meshes = [o for o in bpy.data.objects if o.type == 'MESH' and o.name.startswith('GEO-')]
if not subject_meshes:
    raise RuntimeError("No subject meshes found (looking for GEO- prefix)")

# World-space bbox
deps = bpy.context.evaluated_depsgraph_get()
all_verts = []
for o in subject_meshes:
    eo = o.evaluated_get(deps); em = eo.to_mesh()
    for v in em.vertices:
        all_verts.append(o.matrix_world @ v.co)
    eo.to_mesh_clear()
xs = [v.x for v in all_verts]; ys = [v.y for v in all_verts]; zs = [v.z for v in all_verts]
center = Vector(((min(xs)+max(xs))/2, (min(ys)+max(ys))/2, (min(zs)+max(zs))/2))
height = max(zs) - min(zs)
width = max(xs) - min(xs)
biggest = max(height, width)

# Frame fit: at distance D, vertical frame = D × (sensor_h / focal). Solve for D.
focal_mm = 60        # 60mm gives a flattering not-too-wide hero shot
sensor_h_mm = 24     # full-frame
frame_per_meter = sensor_h_mm / focal_mm   # 0.4 m vertical frame per metre of distance
target_fill = 0.80
camera_distance = biggest / (frame_per_meter * target_fill)

# Camera positioned in front (negative Y) with slight X offset for a 3/4 angle
cam_pos = Vector((center.x + camera_distance * 0.3, center.y - camera_distance, center.z))

# Empty for tracking
empty_name = 'Empty-camera_target'
empty = bpy.data.objects.get(empty_name) or bpy.data.objects.new(empty_name, None)
if empty.name not in [o.name for o in bpy.context.collection.objects]:
    bpy.context.collection.objects.link(empty)
empty.location = center

# Camera
cam_data = bpy.data.cameras.new('CAM-hero')
cam_data.lens = focal_mm
cam_data.dof.use_dof = True
cam_data.dof.aperture_fstop = 4.0
cam_data.dof.focus_object = subject_meshes[0]   # focus on first/main subject

cam = bpy.data.objects.new('CAM-hero', cam_data)
bpy.context.collection.objects.link(cam)
cam.location = cam_pos

track = cam.constraints.new('TRACK_TO')
track.target = empty
track.track_axis = 'TRACK_NEGATIVE_Z'
track.up_axis = 'UP_Y'

bpy.context.scene.camera = cam
print(f"camera:bbox_aware center={tuple(round(v,2) for v in center)} dist={camera_distance:.2f}m focal={focal_mm}mm")