Telecentric Lens FOV & Magnification Calculator
Enter either the magnification or the required field of view. The tool derives the other value, checks sensor coverage and working distance, and lists POMEAS telecentric lenses that fit.
Calculator
Formula and applicable conditions
| Magnification from field of view | β = sensor width / FOV width |
|---|---|
| Field of view from magnification | FOV = sensor size / β |
| Object-side pixel size | p_obj = camera pixel pitch / β |
| Depth of field (theoretical) | DOF ≈ 2 × c × N × (β + 1) / β² with c = 0.04 mmc = 0.04 mm is the permissible circle of confusion used in POMEAS telecentric datasheets. The datasheet note states that roughly half the calculated range is recommended for practical use. |
Parameter definitions
| Optical magnification | Fixed magnification of the telecentric lens (for example 0.118X, 0.5X, 2.0X). |
|---|---|
| Field of view | Object area imaged on the sensor. |
| Sensor size | Effective sensor width and height of the camera. |
| Working distance | Datasheet working distance of telecentric lenses is fixed; deviation changes magnification and calibration. |
| F-number | Used for the theoretical depth of field estimate. |
Worked example
- A 2/3-inch camera (8.8 × 6.6 mm) with a 0.118X telecentric lens gives FOV = 8.8 / 0.118 = 74.6 × 55.9 mm.
- With 3.45 µm pixels, the object-side pixel size is 3.45 / 0.118 = 29.2 µm/px.
- A 0.1 mm feature covers about 3.4 pixels — adequate for detection, but not sufficient for tight dimensional measurement.
Frequently asked questions
Can the object-side pixel size be quoted as measurement accuracy?
No. Object-side pixel size is theoretical sampling. Measurement accuracy also depends on calibration, lighting, algorithm, temperature drift and part fixturing. Do not convert pixel size directly into a measurement accuracy claim.
Why is the working distance important for a telecentric lens?
A telecentric lens is designed for a specific working distance. Outside that distance the magnification changes and the telecentric error grows. The tool reports the deviation from the datasheet value as a gap when it is known.
What does 'sensor coverage' check?
It compares the camera sensor diagonal with the nominal maximum sensor format stated in the lens datasheet. A camera larger than the lens image circle will show vignetting.
Are depth of field values guaranteed?
No. The depth of field shown is a theoretical estimate based on a 0.04 mm circle of confusion. POMEAS datasheets recommend about half the calculated range for practical work, and the final value must be verified on the real part.
Request a POMEAS lens recommendation
Submit the parameters and the calculation result below. The form posts to the existing POMEAS contact interface; nothing is sent automatically and no data is shared with third parties.