Rectilinear S-mount lenses that keep straight lines straight, from 1.8mm wide angle to 35mm telephoto. Datasheets with distortion plots are on each product page.
Inspection systems, mobile robots, and ADAS cameras read geometry straight off the sensor, so the distortion budget gets set before anything else. The notes below cover the field of view tradeoff, what software correction costs, and which designs hold the straightest lines.
24 rectilinear and near-rectilinear S-mount designs from $19. Titles state the nominal focal length; datasheets carry the distortion plot. Sold-out designs are hidden; contact engineering for restock dates.
No distortion means very low residual distortion, not zero; physics does not give you zero. A good rectilinear design holds the residual small enough that straight lines stay straight for measurement and machine vision work.
Rectilinear projection keeps scene geometry intact. Unlike fisheye optics that bow edges outward, a rectilinear lens holds consistent geometry across the frame, so measurement code and detection models get clean spatial input without a dewarp step.
Use these where residual distortion eats the error budget:
For the distortion mechanics behind these claims, see wide-angle lenses and fisheye camera lens distortion.
Low distortion M12 lenses trade a little geometric perfection for a wider field of view. Straight lines still read straight and calibration stays simple; coverage takes priority over metrology-grade accuracy.
Use these when the camera navigates rather than measures:
Distortion grows with field angle, so wider coverage is harder to keep straight: a 6mm design typically holds cleaner geometry than a 2.8mm on the same sensor. Fighting barrel distortion? First ask whether you need that wide a view. Narrowing the field sidesteps the problem, if you can live with less coverage.
You can dewarp in software, at a cost: interpolation softens edges, correction adds latency, and the remap loses resolution at the frame edge. For real-time systems or pixel-level measurement, start with a lens that does not need much correction.
A lens designed for a 1/2" image circle will not cover a 1" sensor; expect vignetting, soft corners, and degraded edge geometry. Verify active-area dimensions against CMOS sensor sizes and check chief ray angle compatibility with your sensor.
Then verify coverage and framing with the camera field of view calculator.
| Feature | 歪みなし | 低歪み | フィッシュアイ |
|---|---|---|---|
| Projection type | 直線的な | Near-rectilinear | Curvilinear |
| Geometry accuracy | 最高 | 高 | 低 |
| Measurement suitability | はい | Depends on tolerance | いいえ |
| Typical field of view | Narrow to moderate | Moderate to wide | Ultra-wide, 180° and beyond |
Need the ultra-wide end instead? Browse M12 fisheye lenses, where the curvature is the projection working as designed.
Distortion directly limits measurement accuracy: uncorrected barrel stretches dimensions toward the frame edge, and on tight-tolerance parts that error turns a pass into a fail. See our guide on image quality and computer vision.
Navigation stacks calibrate more simply on near-rectilinear input. A low distortion wide angle lens gives mobile robots scene coverage without pushing the pipeline into fisheye calibration models. Platform picks are in lenses for robotics and lenses for drones.
Lane detection works better when lanes render straight, and neural nets trained on rectilinear data lose accuracy behind curved geometry. See lenses for autonomous vehicles and our IP67-rated automotive M12 lenses.
Pick-and-place and alignment systems need a consistent pixel-to-millimeter mapping. Distortion drifts the calibration, and then the arm lands 2mm off target and someone is debugging at 2am.
Spec the lens before you buy:
Lens distortion is the departure of image height from the lens’s stated projection: magnification changes with field angle, so straight lines render curved even in a sharply focused image. It is a geometric aberration, separate from blur or vignetting, and it grows toward the field edge. Distortion is quoted against a reference mapping and a measurement image circle, which is why the same lens can carry different numbers on different sensors.
Barrel distortion bows straight lines outward and is common in wide angle lenses. Pincushion distortion pinches lines inward and shows up in telephoto designs. Mustache distortion mixes the two: barrel near center, pincushion at the corners. Sign convention: negative means barrel, positive means pincushion.
Barrel distortion is where magnification decreases with distance from the optical axis, so straight lines curve outward like a barrel. For conventional lenses it is a third-order (Seidel) aberration that grows with field angle. It also buys coverage: for a given focal length, more barrel distortion means a wider field of view, which is why wide angle and fisheye designs carry the most.
A rectilinear lens maps ray angle to image height as r = f·tan(θ), which keeps straight lines in the scene straight in the image. Every lens in this collection is rectilinear or near-rectilinear; fisheye lenses intentionally use different projections to reach 180° and beyond. Rectilinear rendering is what measurement, inspection, and lane detection algorithms assume.
In this collection, the No Distortion 4.4mm (CIL043) carries the tightest label, and the telephoto end measures low naturally: distortion is easier to control at longer focal lengths over narrower fields, so a 6mm or 8mm design typically measures lower than a 2.8mm. Check the distortion plot on the datasheet rather than the product name; the measurement image circle matters.
A marketing term. No lens has exactly zero distortion; a good rectilinear design holds the residual low enough that straight lines look straight and the error disappears inside your measurement budget. Commonlands lists distortion per lens on the datasheet, so you can hold the claim against a number.
Yes, within limits. Calibration models the distortion (Brown-Conrady for near-rectilinear lenses, Kannala-Brandt for fisheye), and dewarping resamples the image against the model. The costs: interpolation softens edges, correction adds latency, and the remap can crop the field. For measurement and latency-sensitive pipelines, starting with clean optics beats fixing geometry every frame.
Start with the optics. Pick a rectilinear design with low residual distortion, and do not buy more field of view than the application needs, since distortion grows with field angle. Match the lens image circle to your sensor so the corners stay inside the well-corrected field. Then check coverage with the FOV calculator, which accounts for distortion.
Tell us your sensor format and field of view requirements, and we’ll point you to the right lens. Samples ship the same day for orders placed before 12 PM PT. No minimum order.
