Camera module

01

Set the field of view from sensor size and focal length

Edmund Optics gives the angular field of view of a fixed focal length lens as AFOV = 2 × arctan(H / 2f), where H is the sensor width and f the focal length: for a given sensor, a shorter focal length gives a wider angle. The field of view also changes with working distance and sensor size, and these paraxial values are approximations. [1]

Editorial calculation with that formula, for a sensor 5.6 mm wide: a 4 mm lens gives about 70° horizontal, an 8 mm lens about 39°.

Edmund Optics adds that short focal length lenses can show more distortion, which changes the real angle, and may not cover larger sensors well. Ask the supplier for the measured horizontal, vertical and diagonal field of view and distortion of the lens fitted. [1]

Give the supplier the scene: object size, working distance, smallest detail to see, motion speed, lighting, and the processor or host and its camera interface.

02

Choose sensor size, pixel size and shutter

Edmund Optics notes that sensor format names such as 1/3 in or 1/2 in come from old Vidicon tubes and do not equal the sensor's dimensions. Edmund Optics states that "Common pixel sizes are between 3 - 10μm" and that "Large pixels have, in general, high charge saturation capacities and high signal-to-noise ratios (SNRs)"; smaller pixels give more resolution for the same sensor size but more blooming and crosstalk. [2]

Edmund Optics writes that the multiplexing configuration of a CMOS sensor "is often coupled with an electronic rolling shutter"; with extra transistors per pixel, a global shutter exposes all pixels at the same time before readout. If objects move fast, ask whether a global-shutter sensor is available, and check exposure time and frame rate at full resolution. [2]

03

Match the interface to the host

Camemake lists modules from 0.3 MP to 200 MP with USB, MIPI CSI-2, GMSL, DVP and SPI outputs; Hampo lists USB, SoC and MIPI modules; CCDCAM lists IP (network) camera modules. Check the interface your processor supports, its drivers, and cable length. [3] [4]

For production, ask how the lens is focused and fixed; Sincere describes active alignment in its module manufacturing. Ask for focus and image-quality test results per batch. [6]

04

USB, global-shutter, network, machine-vision, micro and surveillance modules on the linked sites

ELP lists USB modules including a 2 MP global-shutter module with an M12 lens; CCDCAM lists network modules built on IMX-series sensors; Sincere lists machine-vision camera modules; Focuslight lists micro camera modules; Lite-On lists camera modules for surveillance. These are suppliers' own descriptions. [5] [3]

05

Image sensor, lens, lens alignment and fixing, board and interface, housing

The alignment-and-fixing row holds focus over the module's life; Sincere describes active alignment in its module manufacturing, so ask how focus is set, fixed and tested per batch. [6]

06

Resolution, sensor format, pixel size, field of view, focal length and interface for a camera module order

The sensor and optics rows carry Edmund Optics relationships; aperture, temperature, supply, power, weight and dimensions have no published value here and must come from the module datasheet. [1] [2]

07

Send the scene, host and production data together

Paste it into your enquiry below or into an email to a maker, then replace every bracket.

Scene: [object size; working distance; smallest detail; motion; lighting]
Optics: [field of view; focal length; distortion limit; mount]
Sensor: [resolution; pixel size; shutter (rolling or global); frame rate; colour or mono]
Host: [processor; interface; drivers and OS; cable length]
Environment: [temperature; vibration; enclosure]
Production: [quantities; focus and test method; lifecycle of sensor]
Documents: [datasheet; test images; drawing]

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