Solving a very serious problem.

possible_cameras.py

#!/usr/bin/env python

from collections import namedtuple

CoC = 0.018 # canon APS-C
MIN_DISTANCE = 100 # must focus 300mm away
MAX_DISTANCE = 1 * 1000 * 1000 # must focus one KM away

FOCALS = [1.3 + (x/10.0) for x in xrange(1, 40 * 10)]
FOCUS_DISTANCE = [100 * x for x in xrange(1, 10)]
APERATURES = [1.3 + (x/10.0) for x in xrange(1, 10 * 90)]

CameraSettings = namedtuple("CameraSettings", "focal aperature focus_distance")
Result = namedtuple("Result", "camera_settings min_focus max_focus")

def calcHyperfocal(focalLength, aperature):
    return (focalLength * focalLength) / (aperature * CoC)

def calcNearPoint(hyperfocal, distanceMM, focalLength):
    return (hyperfocal * distanceMM) / (hyperfocal + (distanceMM - focalLength))

def calcFarPoint(hyperfocal, distanceMM, focalLength):
    return (hyperfocal * distanceMM) / (hyperfocal - (distanceMM - focalLength))

def calcTotalDoF(hyperfocal, distanceMM, focalLength):
    return (calcFarPoint(hyperfocal, distanceMM, focalLength) - 
            calcNearPoint(hyperfocal, distanceMM, focalLength))

def printValidFocalLengths():
    results = []
    for focal in FOCALS:
        for aperature in APERATURES:
            for distance in FOCUS_DISTANCE:
                hyperfocal = calcHyperfocal(focal, aperature)
                near = calcNearPoint(hyperfocal, distance, focal)
                far = calcFarPoint(hyperfocal, distance, focal)
                camera = CameraSettings(focal=focal, aperature=aperature, focus_distance=distance)
                result = Result(camera_settings=camera, min_focus=near, max_focus=far)
                if result.max_focus > 0:
                    results.append(result)
    meetsBoth = [item for item in results if item.min_focus <= MIN_DISTANCE and item.max_focus >= MAX_DISTANCE]
    for item in meetsBoth:
        print(item)
            
def toFeet(mm):
    return (3.28084 * mm) / 1000



if __name__ == "__main__":
    printValidFocalLengths()