import json
import bpy

# Get all cameras
cameras = []
for cam_obj in bpy.data.cameras:
    user_map = bpy.data.user_map(subset={cam_obj}, value_types={'OBJECT'})
    for data_obj in user_map[cam_obj]:
        cam = {'name': data_obj.name, 'lens': cam_obj.lens}
        cameras.append(cam)

data = {'cameras':  cameras,
        'frame_start': bpy.data.scenes[0].frame_start,
        'frame_end': bpy.data.scenes[0].frame_end,
        'resolution_x': bpy.data.scenes[0].render.resolution_x,
        'resolution_y': bpy.data.scenes[0].render.resolution_y}

data_string = json.dumps(data)
print("SCENE_DATA:" + data_string)