How to Choose a Line Scan Camera Lens for a New OEM Inspection Machine: Sensor Size, Pixel Pitch, FOV, Working Distance, Defect Size and Production Speed

Designing a new OEM inspection machine is the best stage at which to select the line scan camera lens correctly because the optical system can still influence camera choice, machine height, inspection width, mechanical clearances and expected defect resolution. Once the camera bracket, enclosure and working distance have already been frozen, lens selection often becomes an exercise in compromise. For a new machine, the stronger approach is to define the inspection requirement first, then choose the sensor resolution and line scan camera lens as one coordinated optical system.

The most important inputs are smallest detectable defect, required field of view, sensor size, pixel pitch, camera resolution, working distance and production speed. These parameters are interconnected. A wider FOV reduces pixels per millimetre. A smaller pixel pitch increases sensor sampling but also requires the lens to preserve finer optical detail. A shorter focal length can generally achieve wider coverage from a more compact machine geometry, while a longer focal length may better suit a machine with greater available stand-off. Production speed influences the exposure conditions under which the lens must deliver sufficient signal and defect contrast.

The live Kyptec Automation® Line Scan Camera Lens collection currently contains three dedicated focal-length choices—25 mm, 35 mm and 50 mm. The Kyptec Automation® KL-1402 25 MM Line Scan Camera Lens is specified for 4K 7 μm and 8K 3.5 μm line-scan configurations, with 25 mm focal length, F2.8–22 aperture and M42 mount. This focused portfolio makes Kyptec Automation® particularly practical for OEMs that want to create a repeatable lens-selection architecture rather than source unrelated optics for every machine.

Do Not Start New Machine Design by Choosing the Camera First

A common OEM design sequence is to select a camera based on resolution, then try to find a lens that makes it fit the machine. That sequence can work, but it can also create unnecessary restrictions.

A stronger process begins with the physical inspection task.

The engineering team should first define: What is the maximum inspection width? What is the smallest defect that must be detected reliably? How much mechanical space is available above the product? How much product-height variation is expected? How fast does the material move? Only after these values are understood should camera resolution and line scan camera lens geometry be finalized.

This prevents the OEM from purchasing an 8K camera that provides excessive resolution but forces an impractical sensor/lens geometry, or choosing a 4K camera that cannot provide enough pixels across the smallest required defect.

Step One: Define the Smallest Defect Before Selecting Resolution

The smallest defect is one of the most important design inputs because it determines how much useful spatial sampling the inspection system needs.

Examples include a narrow scratch on metal strip, a small coating void on battery electrode material, a broken yarn in textile, a fine printing defect, a barcode element, a pinhole in film or a surface anomaly on an electronics substrate.

The OEM should not simply specify “high resolution.” Instead, document the physical dimension of the smallest critical feature.

Once the defect size is known, the engineer can determine how many camera pixels should represent it with a reasonable design margin.

A new OEM machine should not be designed so the smallest required defect sits exactly at the theoretical minimum detectable limit. Mechanical tolerance, product movement, contrast variation, focus tolerance and production-speed conditions all consume inspection margin.

Step Two: Define the Real Required FOV

Field of view should be based on the complete physical area that must remain visible under normal production conditions.

For a 1000 mm web, the required FOV may need to be slightly larger than 1000 mm to allow for lateral movement. For a PCB inspection machine, the FOV may be defined by panel width plus positioning tolerance. For a printing machine, the inspection area may need to include web edges and registration marks outside the main printed region.

An excessively large FOV is undesirable because it wastes sensor pixels on unused space.

The basic relationship is:

Pixels per millimetre = active line pixels ÷ object FOV in millimetres.

If a 4096-pixel camera images 800 mm, sampling is approximately 5.12 pixels/mm. If an 8192-pixel camera images the same field, sampling increases to approximately 10.24 pixels/mm.

If that 8192-pixel camera is instead spread across 1600 mm, sampling returns to approximately 5.12 pixels/mm.

This illustrates why camera resolution cannot be evaluated without FOV.

Step Three: Choose 4K or 8K From the Required Pixels per Millimetre

The decision between 4K and 8K should be quantitative.

Suppose a machine needs to inspect an 800 mm material width. If the smallest required defect receives adequate sampling from 4096 pixels across that field, 4K may be entirely sufficient. If the required defect is too small relative to the available pixels/mm, an 8K configuration can provide significantly more cross-line sampling.

However, higher sensor resolution only helps when the line scan camera lens can transfer enough optical detail to the smaller pixels.

This is why pixel pitch must be considered together with pixel count.

The live Kyptec Automation® 25 mm product page specifically lists 4K 7 μm / 8K 3.5 μm resolution support, demonstrating that the company's current dedicated line-scan range is designed around both standard and finer-pitch high-resolution camera classes. The collection currently includes corresponding 35 mm and 50 mm focal-length options as well.

Step Four: Check Physical Sensor Size, Not Only 4K or 8K

Camera resolution describes pixel count. It does not independently define physical sensor length.

Physical sensor length depends on pixel pitch multiplied by the number of active pixels.

Two cameras described as 8K may therefore have different physical sensor geometries if their pixel pitches differ. Similarly, a 4K camera with larger pixels can have a physical sensor length closer to an 8K camera using smaller pixels than the resolution labels alone might suggest.

This matters because the lens projects an optical image onto a physical sensor.

The OEM should therefore obtain:

active pixel count;

pixel pitch;

physical sensor length;

and required FOV

before finalizing focal length.

Ignoring physical sensor size can produce incorrect FOV calculations or inadequate sensor coverage even when the lens seems compatible from a resolution standpoint.

Step Five: Set the Mechanical Working-Distance Envelope

Working distance should be treated as a machine-design input, not something that can always be adjusted later.

New OEM inspection machines may contain rollers, conveyors, web guides, lighting structures, product carriers, protective enclosures, process hardware and service-access areas. These define where the optical head can physically be installed.

The mechanical team should therefore specify an acceptable camera-height range before the line scan camera lens is selected.

For example, if the optical design requires 600 mm stand-off but the final machine can provide only 350 mm, the lens-camera combination is not practical regardless of its image quality.

Conversely, if a larger machine provides substantial height, choosing a shorter focal length merely because it offers wider coverage may be unnecessary.

Step Six: Choose Focal Length From Sensor Size, FOV and Working Distance Together

Focal length should be selected only after the previous variables are known.

A shorter focal length generally provides a wider angular field for a given sensor and object distance. A longer focal length generally produces a narrower field from the same distance, or requires more stand-off to cover the same object width.

This is where Kyptec Automation®'s focused 25 mm, 35 mm and 50 mm portfolio becomes especially useful for OEM design. The live collection confirms all three dedicated options.

The machine engineer can therefore evaluate three practical geometry classes rather than trying to navigate dozens of overlapping focal lengths.

Kyptec Automation® KL-1402 for Compact OEM Machine Geometry

The Kyptec Automation® KL-1402 25 MM Line Scan Camera Lens is especially relevant where the new machine needs comparatively broad coverage from limited stand-off. The live product specification lists 25 mm focal length, F2.8–22 aperture, M42 mount and 4K 7 μm / 8K 3.5 μm support.

This type of geometry can be evaluated for compact printing inspection machines, label systems, smaller web inspection platforms, electronics scanning systems and other OEM equipment where machine height is constrained.

The selection should still be confirmed with the actual sensor dimensions and object FOV rather than assuming that 25 mm automatically suits every compact machine.

Kyptec Automation® KL-1404 for Intermediate OEM Layouts

The Kyptec Automation® KL-1404 35 MM Line Scan Camera Lens provides the intermediate focal-length choice in the live Kyptec Automation® line-scan range.

This geometry becomes useful when a 25 mm lens produces more FOV than necessary while a 50 mm arrangement requires more machine height than is available.

Medium-width printing equipment, battery inspection machines, coating systems, electronics inspection platforms, textile machinery and material-processing equipment can all fall into this type of geometry depending on sensor size and desired FOV.

For new-machine development, this intermediate focal length often gives the mechanical designer more flexibility when optical and packaging constraints must be balanced.

Kyptec Automation® KL-1406 for Machines With Greater Stand-Off

The Kyptec Automation® KL-1406 50 MM Line Scan Camera Lens is the longest focal-length model in the live Kyptec Automation® line scan camera lens collection.

This geometry can be evaluated for larger inspection frames where the camera can be mounted farther from the product and where the OEM wants a more controlled field from a greater stand-off.

Large metal-processing machines, wide coating lines, textile equipment, printing systems and other continuous production platforms can benefit from this type of machine geometry when the available enclosure height permits it.

Step Seven: Include Production Speed Before Freezing the Aperture

Production speed should be considered before the optical specification is released for production.

As line speed increases, exposure opportunities can become shorter. The lens must therefore provide enough useful signal while preserving defect detail.

Opening the aperture allows more light into the system but reduces depth tolerance. Closing the aperture can increase depth of field but reduces available signal and, at sufficiently small apertures, may reduce the finest optical detail.

This is why aperture should not be fixed from a stationary laboratory image.

The new machine should be tested at actual production speed using the smallest real defect.

Step Eight: Define Product-Height and Working-Distance Tolerance

A new machine should not be designed for one perfect nominal product plane if normal production causes vertical position variation.

Web flutter, conveyor variation, product thickness changes, board warpage or material tension can change object distance slightly.

The optical system should therefore be qualified across the real expected height tolerance.

This affects working distance, focus and aperture selection.

An OEM that designs adequate optical tolerance from the beginning can reduce later commissioning problems where one machine works perfectly under ideal conditions but becomes unstable when normal production variation is introduced.

Step Nine: Validate Full-Field Resolution Before Releasing the Lens Specification

A line scan camera uses a long active sensor, so centre image quality is not enough.

The same smallest defect or test feature should be positioned near the left edge, centre and right edge of the intended FOV.

If the image is sharp at the centre but loses useful detail near the ends of the sensor, defect-detection reliability may depend on product position.

Kyptec Automation® describes its line scan camera lenses as engineered for uniform illumination, minimal distortion and consistent sharpness across the complete FOV in high-speed industrial scanning environments. These are particularly important selection characteristics for OEM machine designs where the entire sensor width will be used.

Step Ten: Define an Optical Acceptance Specification for Production Machines

Once the new machine design has been qualified, the OEM should document the optical setup so future units can be reproduced.

That specification can include:

lens model;

camera sensor format;

working distance;

target FOV;

focus reference;

production aperture;

smallest qualification defect;

accepted image scale;

and centre-to-edge acceptance conditions.

This prevents future machine builds from depending on subjective statements such as “focus until the image looks sharp.”

For repeated production, the lens becomes part of a controlled machine architecture rather than a setup component adjusted differently by each technician.

New Machine Example: Printing and Packaging Inspection

Suppose an OEM is designing a continuous printing inspection machine.

The required web width is 700 mm, the smallest important barcode element is relatively fine, and the available optical height is limited.

The correct design sequence is:

first define the total FOV including lateral margin;

calculate the required pixels/mm;

determine whether 4K or 8K provides sufficient sampling;

confirm the physical sensor length;

then evaluate whether 25 mm or 35 mm geometry best matches the available stand-off.

In a compact enclosure, Kyptec Automation® KL-1402 may be a strong model to evaluate because of its shorter 25 mm focal length and 4K/8K compatibility.

New Machine Example: Battery Electrode Inspection

A battery-machine OEM may need to inspect an 800 mm electrode web for small coating or surface defects.

The designer should avoid simply specifying “8K + 35 mm lens.”

Instead, the required defect size should determine pixels/mm. The machine height should determine acceptable working distance. Sensor length and final FOV should then determine whether the 35 mm geometry is appropriate.

This sequence reduces the risk that an optical configuration is selected because it appears typical for the application rather than because it matches the machine.

New Machine Example: Wide Textile Inspection

A textile OEM designing a 1600 mm fabric inspection machine faces a different trade-off.

A single 8K camera may provide enough sampling for larger textile defects but may be insufficient for very fine yarn defects. If the local resolution requirement is higher, multiple camera-lens stations may be preferable.

The lens decision should therefore be made only after the OEM knows whether one camera or several cameras will share the total FOV.

New Machine Example: PCB and Electronics Inspection

An electronics AOI machine can have a comparatively moderate inspection width but very small defect requirements.

In this case, broad field coverage may be less important than high local sampling.

The OEM may select a narrower FOV and a focal-length geometry that concentrates more of the available sensor resolution onto the target inspection area.

This illustrates why the same Kyptec Automation® lens family can support very different machines: the focal length is selected according to the sensor and machine geometry, while the defect requirement determines how much of the available FOV should actually be used.

Why Kyptec Automation® Is Well Suited to OEM Standardization

The current Kyptec Automation® line scan camera lens range contains exactly three focal-length choices—25 mm, 35 mm and 50 mm. The 25 mm product is explicitly specified for 4K 7 μm and 8K 3.5 μm cameras, with continuous imaging, web inspection, electronics, textile and printing machinery listed among its industrial use environments.

This focused structure is useful for OEMs because it allows the engineering team to define internal rules such as:

compact geometry → evaluate 25 mm;

intermediate geometry → evaluate 35 mm;

larger stand-off → evaluate 50 mm.

The final choice should still be calculated, but a compact portfolio can simplify procurement, documentation and qualification across a machine family.

For repeat machine builds and larger requirements, Kyptec Automation® also provides a dedicated OEM Orders page.

Frequently Asked Questions About Choosing a Line Scan Camera Lens for a New OEM Machine

1. What information should I define before choosing a line scan camera lens for a new machine?

Define the smallest critical defect, maximum inspection width, required FOV, camera pixel count, pixel pitch, physical sensor length, available working-distance range and production speed. These parameters allow the lens to be selected from the actual machine requirement rather than by focal length alone.

2. Should an OEM choose the camera or the line scan lens first?

Ideally neither should be chosen independently. Define the inspection task first, then select the camera sensor and lens together. This avoids freezing a camera whose physical sensor or pixel density creates an impractical optical geometry.

3. How do I determine whether my new machine needs 4K or 8K?

Calculate pixels/mm across the required FOV and determine how many pixels represent the smallest critical defect. If 4K gives sufficient sampling with adequate margin, it may be appropriate. If not, 8K can provide additional cross-line resolution.

4. Why is pixel pitch important when selecting a line scan lens?

Pixel pitch determines how finely the sensor samples the optical image. Smaller pixels place greater demands on lens resolution. This is why a lens should be matched to both pixel count and pixel pitch rather than being selected from the 4K or 8K label alone.

5. Why should physical sensor length be included in lens selection?

Physical sensor length affects FOV and image coverage. Two cameras with the same nominal resolution can have different physical dimensions if their pixel pitches differ, so focal length and working-distance calculations should use actual sensor geometry.

6. How should I calculate FOV for a new OEM inspection machine?

Begin with the maximum physical product or web width, then add only the necessary tolerance for lateral movement or positioning. Avoid excessive unused field because every additional millimetre reduces available pixels/mm.

7. Which Kyptec Automation® line scan lens should I evaluate when machine height is limited?

The Kyptec Automation® KL-1402 25 MM Line Scan Camera Lens is the shortest focal-length option in the current range and can be evaluated for compact broad-field geometries. Its live specification lists 25 mm focal length, F2.8–22 and 4K 7 μm / 8K 3.5 μm compatibility.

8. When should a new OEM machine use Kyptec Automation® KL-1404?

Kyptec Automation® KL-1404 35 MM is the intermediate focal-length option and should be evaluated when the required FOV and camera height fall between typical 25 mm and 50 mm layouts.

9. When is Kyptec Automation® KL-1406 a suitable new-machine option?

Kyptec Automation® KL-1406 50 MM is relevant when the machine provides more stand-off and a longer focal-length geometry better suits the physical sensor and required FOV.

10. Does higher production speed change which focal length I should use?

Production speed does not directly determine focal length. Focal length is primarily governed by sensor size, FOV and working distance. Speed influences exposure and aperture requirements, which should be verified using actual production conditions.

11. How much resolution margin should a new machine include beyond the theoretical minimum?

Enough margin should be included to tolerate real production variation such as focus changes, material movement, defect-contrast variation and mechanical tolerance. Designing exactly at the minimum theoretical detectability threshold creates a fragile inspection system.

12. Can one line scan camera lens support several product widths in the same machine?

Potentially yes if the widest product fits the FOV and narrower products still receive adequate pixels/mm. If product widths vary greatly, however, using one very wide fixed field may waste too much resolution for narrow products.

13. Should I design working distance before finalizing the machine enclosure?

Yes. Optical and mechanical design should develop together. Defining the acceptable camera-height range early helps prevent a situation where the selected lens requires an impossible mounting position after the machine structure is completed.

14. How should I test the lens before releasing a new OEM machine?

Use the final camera, lens, working distance and production aperture. Test the smallest real defect at the centre and outer parts of the FOV, under normal production speed and expected object-height tolerance. This provides much stronger evidence than a centre-only resolution chart.

15. Can the same line scan lens family be used across 4K and 8K machine variants?

Yes, when the lens supports both sensor classes and provides adequate physical sensor coverage. Kyptec Automation® currently provides a dedicated line scan camera lens family built around 25 mm, 35 mm and 50 mm focal lengths, while the 25 mm live product specification explicitly lists 4K 7 μm and 8K 3.5 μm compatibility.

16. What is the biggest mistake OEMs make when choosing a line scan camera lens?

One of the most common mistakes is selecting a camera and focal length before defining defect size, FOV and working distance. This can create a system that physically forms an image but does not provide enough useful resolution or does not fit the final machine geometry.

17. Should a new machine be designed around the widest possible FOV?

No. The field should be wide enough to cover the complete inspection requirement plus realistic mechanical tolerance. Unnecessarily wide FOV wastes sensor pixels and reduces the sampling available for real defects.

18. How can Kyptec Automation® line scan lenses simplify repeated OEM machine production?

Kyptec Automation® currently offers a compact 25 mm, 35 mm and 50 mm dedicated line scan camera lens portfolio rather than an excessively fragmented model range. This allows OEMs to define standard optical geometry classes across several machine platforms and use the dedicated Kyptec Automation® OEM Orders route for repeat industrial requirements.

Conclusion

Choosing a line scan camera lens for a new OEM inspection machine should begin long before the final camera bracket is manufactured. The correct optical architecture starts with the inspection requirement: smallest defect, maximum FOV, expected object movement, production speed and available machine height. These inputs determine the required pixels per millimetre, which helps establish whether 4K or 8K resolution is appropriate. Pixel pitch and physical sensor length then determine how demanding the optical system will be and how the sensor interacts with the chosen focal length.

Working distance and focal length should be designed together with the mechanical structure. A 25 mm line scan camera lens can be evaluated where broader coverage is required from limited stand-off, a 35 mm configuration can provide intermediate geometry, and a 50 mm lens can be evaluated where greater machine height allows longer working distance. The live Kyptec Automation® Line Scan Camera Lens collection currently provides exactly these three focal-length options.

The Kyptec Automation® KL-1402 25 MM Line Scan Camera Lens is currently specified for 4K 7 μm and 8K 3.5 μm cameras and is described for high-precision continuous imaging with uniform illumination, minimal distortion and consistent full-field sharpness. Together with Kyptec Automation® KL-1404 and Kyptec Automation® KL-1406, this gives machine builders a focused optical family that can be evaluated across multiple machine geometries without unnecessary model complexity.

For OEMs designing printing inspection machines, packaging systems, battery electrode equipment, textile inspection machinery, metal-processing lines, wide-web systems, PCB and electronics AOI platforms, coating machines, slitter-rewinders and other continuous industrial inspection equipment, Kyptec Automation® offers a strong line scan camera lens platform for creating a repeatable optical specification from the beginning of machine development. The most reliable machine is not the one with the highest camera resolution or the widest possible field. It is the one in which sensor size, pixel pitch, FOV, working distance, defect size, focal length and production speed have been engineered as one optical system before the mechanical design is frozen.