CALCULATORS / OPTICS, IMAGING AND ILLUMINATION

Camera working distance calculator

Pinhole object distance from sensor extent, focal length and field size.

optics-working-distance.napkin / editable

SCENARIO COMPARISON

Compare the numbers.

This source describes an analytical model. Its quantities and checks are the view.

Scenario	distancemm
	250
	312.5

All calculated quantities are listed with the inputs. Switch to Source to inspect the equations.

SCENARIOS / CALCULATED VALUESSAME SOURCE

Change an input to see the consequences.

working distance budget250.00 mm✓ passes

BASELINE INPUTS

sensor6.4 mmfocal8 mmfield200 mm

CALCULATED

distance250 mm

Edits change the baseline source.

THE SOURCE

Edits below update the same model.

# Camera working distance
# Scope: Pinhole object distance from sensor extent, focal length and field size.
# Status: illustrative worked example; engineering review pending.
# Inputs are example values. Checks are editable example requirements, not standards.

sensor = 6.4 mm
focal = 8 mm
field = 200 mm

distance := focal*field/sensor [mm]

check working distance budget: distance <= 300 mm

scenario alternative: sensor = 5.12 mm

Calculated from your source · not saved

Baseline · Baseline

working distance budget250.00 mm ✓ passes

alternative · alternative

working distance budget312.50 mm × fails

Illustrative first-order example. Checks are editable requirements, not design standards. The broader topic may require additional equations, data, and validation.

Formula and units

This example uses the following equations. Input names and units match the editable source above.

distance: distance = focal*field/sensor [mm]

Original worked example

These are the baseline values in the downloadable source. Edits above let you test your own values.

Given

sensor: 6.4 mm
focal: 8 mm
field: 200 mm

Calculated

distance: 250 mm

Assumptions and limits

Pinhole object distance from sensor extent, focal length and field size.

The requirement checks use the limits written in this example. Passing a check does not establish that the model covers every load, material behavior, or operating condition in a real design.

Download this .napkin example ↓

Take it further with your agent

Napkin keeps the inputs, equations, checks and assumptions together in one study. Your agent sets it up; you change the numbers.

Try with Claude ↗

codex 'Use Napkin (https://napkin.engineering/mcp, or the local Napkin plugin) to build a study: Camera working distance. Inputs: target field; sensor; lens model. Outputs: working distance; magnification. Model scope: Paraxial geometry or calibrated radiometric/photometric models. Read napkin_capabilities and the current snapshot. Ask me for the values that matter, label assumptions with units, author .napkin source, validate it and apply it with napkin_source using the current revision, then open the study. Add checks for the limits I supply. Keep unsupported analyses explicit.'

Claude needs the Napkin connector; Codex needs the Napkin plugin. Set up your agent ↗

The broader study

The topic brief below describes the broader scope. The worked example above states the particular calculation it implements.

Inputs: target field, sensor, lens model
Outputs: working distance, magnification
Modes: calculate, compare, sweep
Drawing: Ray diagram and camera view

EXECUTABLE WORKED EXAMPLE · FIRST-ORDER MODEL · CHECK THE SCOPE & ASSUMPTIONS