Choose optics and control blur and distortion

Questions covered here

Start here for image scale, focal length, exposure, motion blur, depth of field, shutter timing and calibration.

The calculation gives you a starting point. Whether the setup works is decided by the exact camera, lens, light and mechanics, tested on representative samples.

Guides in this direction

• Deciding whether a measurement needs a telecentric lens, and choosing one — Estimate how much a regular lens changes the measured size when a part sits off the calibration plane, and plan a telecentric lens when that estimate alone uses up your measurement budget or an angled view hides an edge that a straight-on view would show. Choose it by magnification, since the field is the sensor size divided by magnification, check field, depth and image circle against the part, and accept it on the calibrated error measured at both height extremes.
• How to calculate lens focal length and field of view when the working distance is fixed — Calculate the focal length from the active sensor size, the field you need and the working distance counted from the lens principal plane. Then check the real field and pixels per millimetre of the catalog lens you pick.
• Checking whether a lens fits your camera: image circle, sensor diagonal and mount — A format label such as 2/3″ names a size class, not a measurement. Compare the lens image circle with the sensor's active diagonal in millimetres, then check mount, thread and flange distance separately.
• Deciding how many pixels a feature needs before you choose a camera — Spotting a feature, measuring it and rejecting parts on it each need their own pixel budget. The calculator gives the sampling, while detection, measurement error and reject rates come from tests on real parts.
• Deciding whether a rolling shutter is good enough for your moving part — A moving part does not rule out a rolling shutter. Shift the reference points by the part's travel between row times, recompute the dimension and budget blur separately.
• Deciding whether depth of field covers every part position — Pick the lowest f-number whose calculated depth of field covers every part position plus your reserve. Then prove it with the real decode or measurement at the nearest and farthest positions.
• Setting exposure for a moving part, and deciding whether to pulse the light — Turn line speed and the blur you accept into a time limit. Then decide whether it limits the camera exposure or a synchronized light pulse, worked through for a code on a conveyor.

Related

• Solve a machine vision engineering task

How this material was prepared

Prepared by MVisionPro from the stated sources and the MVisionPro calculation engine. A physical test is claimed only when the material says so explicitly. Read the editorial method.

Editorial status: verified. Content updated 2026-09-23.