Kowa industrial lenses cover fixed-focal, NIR/SWIR, line-scan, S-mount, telecentric and zoom series. Selection hinges on four variables: sensor size, resolution, working distance (or field of view) and mount. This article gives an actionable path along these four axes.
1. Start with sensor size and resolution
The lens image circle must be no smaller than the camera sensor. Otherwise corners show vignetting or a sharp drop in resolution. Common formats include 1/2″, 2/3″, 1″, 1.1″ and 4/3″; the larger the sensor, the higher the image-circle and resolution requirement.
- 2/3″ and below: most fixed-focal and zoom series suffice;
- 1″~1.1″: prefer fixed-focal series specified for that format;
- 4/3″ and above: choose large-format lenses to avoid edge degradation.
Also check pixel size: smaller pixels demand higher lens resolution (5MP, 12MP, 24MP and up).
2. Derive focal length or magnification from working distance and FOV
For fixed-focal lenses: focal length ≈ sensor size × working distance ÷ field-of-view width. For telecentric lenses, choose by magnification (Mag) and working distance (WD). Tight WD constraints (e.g. confined fixtures) call for short-WD or special-structure lenses.
3. Typical applications by Kowa series
| Series | Strength | Typical use |
|---|---|---|
| Fixed-focal | High resolution, low distortion | General machine vision, positioning |
| Telecentric | Low distortion, constant magnification | Precision dimensional measurement |
| Line-scan | Large image circle, high definition | Line-scan inspection, print/film |
| NIR/SWIR | NIR/SWIR transmission | Agriculture sorting, penetration inspection |
| S-mount (M12) | Compact, low cost | Small/embedded cameras |
| Zoom | Adjustable focal length | Frequently changing FOV |
4. Mount and mechanical clearance
Ensure the lens mount (C / CS / M12 etc.) matches the camera, and check total length and diameter against fixtures and light sources. For a CS-mount camera, a C-mount lens needs a 5mm spacer — see the C/CS/M12 mount guide.
5. FAQ
How to balance resolution and sensor size?
First filter out models with insufficient image circle, then screen by pixel size and required MTF/resolution, and finally fix focal length by working distance.
Do large-format setups always need telecentric lenses?
No. Prefer telecentric when dimensional accuracy matters; large-format fixed-focal lenses are fine for general imaging.
Browse the full Kowa lens series and models, or use the online selector to filter by parameters.