Zoom Lens Magnification & FOV Calculator
Calculate system optical magnification, field of view and object-side pixel size for a POMEAS continuous zoom lens combined with a TV tube and an APO objective. Candidate models are selected from the POMEAS datasheet database.
Calculator
Formula and applicable conditions
| System optical magnification | β = β_body × β_TV × β_APO × kk is the combination correction factor. It is combination-specific and must be taken from the datasheet; it is NOT a universal constant. |
|---|---|
| Field of view | FOV_H = sensor width / β ; FOV_V = sensor height / βSensor dimensions are the effective sensor size of the camera, not the nominal sensor format alone. |
| Object-side pixel size | p_obj = p_camera / βp_camera is the camera pixel pitch in µm. Object-side pixel size is the theoretical sampling limit, not a measurement accuracy figure. |
Parameter definitions
| Effective sensor width / height | Active imaging area of the sensor in mm. Take it from the camera datasheet; the nominal inch format is only a label. |
|---|---|
| Effective pixels (H) | Number of active pixels across the sensor width. Used to derive pixel pitch when it is not given. |
| Camera pixel pitch | Physical pixel size in µm. |
| Body magnification | Magnification of the zoom lens body at the selected zoom position. |
| TV tube magnification | Magnification of the TV tube / adapter (common values 0.5X, 1X, 2X). |
| APO objective magnification | Magnification of the附加 objective (none = 1X). |
| Combination correction factor k | Correction for a specific objective + tube combination. Must be verified per combination. |
Worked example
- Camera: 2/3-inch sensor, 8.8 × 6.6 mm, 2448 × 2048 pixels (3.6 µm pitch).
- Lens: PMS-LZ-650104 at 0.7X, TV tube 1X, no APO objective (k = 1).
- Result: β = 0.7X, FOV = 12.57 × 9.43 mm, object-side pixel size = 5.14 µm/px.
- A 10 µm feature therefore covers about 1.9 pixels — below the usual 3-pixel sampling rule, so a higher magnification or a smaller-pixel camera is needed for reliable detection.
Frequently asked questions
Is system magnification the same as display magnification?
No. System optical magnification is an object-side optical ratio. Display magnification also depends on the monitor size and the digital zoom of the software. This calculator reports object-side optical magnification only.
Can I use 0.55 as the correction factor for every combination?
No. 0.55 is a combination-specific coupling coefficient used for the POMEAS APO objective series under the current site convention. Other objectives, third-party tubes or unlisted combinations must be verified against their own datasheet before use.
Why does my measured field of view differ from the calculation?
The calculation uses the nominal sensor size and nominal lens magnification. Real differences come from sensor tolerances, zoom position repeatability, mechanical tolerances and the exact mechanical interface. Treat the result as a design value and confirm with a sample test.
Which POMEAS zoom lenses support 1-inch sensors?
The 4K zoom lens series (for example the PMS-LZH-75xx family) supports sensors up to 1 inch. They must not be specified for 1.1-inch cameras. The candidate list in this tool enforces that limit.
Request a POMEAS lens recommendation
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