2/3 Inch vs 1 Inch vs 1.1 Inch Machine Vision Lens: How to Match the Lens with Camera Sensor Format

Choosing between a 2/3 inch, 1 inch and 1.1 inch machine vision lens is mainly a question of sensor coverage. The lens must create an image circle large enough to illuminate the complete active area of the industrial camera sensor while maintaining acceptable image quality from the centre to the corners.

This sounds straightforward, but sensor format is one of the most commonly misunderstood specifications in machine vision. Buyers often assume that a lens marked 1 inch simply refers to a sensor measuring exactly one inch across. It does not. Optical format labels such as 2/3 inch, 1 inch and 1.1 inch are historical format classifications rather than direct measurements of the active sensor width or diagonal.

That distinction matters when selecting an industrial camera lens.

A lens intended for a smaller image format may physically mount on a camera with a larger sensor, especially when both use a C mount, yet still fail optically because its image circle does not adequately cover the sensor. The result can be dark corners, reduced edge sharpness, stronger shading or an inspection area that cannot use the complete sensor.

At the same time, simply buying the largest format lens for every camera is not necessarily the best engineering approach. Sensor coverage must be considered together with focal length, resolution, pixel size, mechanical dimensions, working distance and the area that actually needs to be inspected.

Kyptec Automation® provides a broad range of machine vision lenses covering different image formats, focal lengths and resolution classes. This allows an industrial camera lens to be selected around the sensor actually being used rather than treating all C mount cameras as optically identical.

What Does Sensor Format Mean on a Machine Vision Lens?

The image format specified for a machine vision lens indicates the approximate maximum sensor class the lens is designed to cover.

If a lens is marked for a 2/3 inch image format, it is intended for cameras whose sensor dimensions fall within that compatible format range. A 1 inch machine vision lens is designed to cover a larger sensor class. A 1.1 inch machine vision lens is intended for still larger imaging areas.

The important word is coverage.

A lens projects a circular image behind itself. The rectangular camera sensor sits inside that image circle. For the complete sensor to be usable, the lens needs to provide sufficient illumination and optical performance over the sensor's full active diagonal.

If the sensor extends beyond the useful image circle, the outer regions may not receive a properly formed image.

That is why sensor format is an optical compatibility specification rather than simply a naming convention.

Why 2/3 Inch Does Not Mean the Sensor Is 16.9 mm Wide

A common mistake is to convert the nominal optical format directly into millimetres.

Two thirds of an inch is approximately 16.9 mm, but a 2/3 inch machine vision sensor does not normally have an active imaging width of 16.9 mm.

The same principle applies to 1 inch and 1.1 inch format descriptions.

These terms originated from older imaging conventions and should not be interpreted as literal active sensor measurements.

For lens selection, the camera datasheet is more useful than the nominal label alone. Look for the active sensor width, active sensor height and sensor diagonal.

When precise compatibility matters, those actual dimensions should be compared with the lens specification.

This is particularly important with newer industrial image sensors because two cameras described using broadly similar format terminology can differ slightly in active dimensions.

The Image Circle Is the Real Reason Sensor Format Matters

Every machine vision lens produces a finite usable image circle.

Imagine placing a rectangular sensor inside that circle.

A smaller 2/3 inch sensor can fit inside a relatively modest image circle. A larger 1 inch sensor needs a larger circle. A 1.1 inch sensor needs still greater coverage.

This is why a larger format lens can often be used with a smaller compatible sensor, while the reverse arrangement is more likely to cause problems.

For example, a properly chosen 1 inch lens may cover a 2/3 inch sensor because the smaller sensor uses only the central portion of the lens image. A 2/3 inch lens used on a significantly larger 1 inch sensor may not provide equivalent coverage at the corners.

That does not mean every larger format lens is automatically ideal for every smaller camera. Focal length, mount, optical resolution and other specifications still matter. It simply explains the direction in which sensor coverage compatibility usually works.

What Is a 2/3 Inch Machine Vision Lens Best Suited For?

A 2/3 inch machine vision lens is widely relevant to compact industrial cameras using sensors within that image format class.

These lenses can be suitable for factory automation, presence inspection, component verification, measurement, code reading, electronics inspection, packaging inspection and many other applications where the camera sensor does not require a larger image circle.

One practical advantage of using a lens designed around the camera's actual sensor size is efficient system matching. The lens does not need to be oversized optically simply because larger sensor formats exist.

Kyptec Automation® provides multiple 2/3 inch options across different focal lengths and resolution requirements. For example, Kyptec Automation® KL-1208 25 mm 5 MP Machine Vision Lens is specified with a 2/3 inch image format, 25 mm focal length and C mount. For higher resolution imaging within the same sensor format class, Kyptec Automation® KL-1222 8 mm 10 MP Machine Vision Lens is a 10 MP, 8 mm C mount option.

The presence of multiple focal lengths and resolution classes is important because “2/3 inch lens” identifies only the sensor coverage requirement. It does not tell you the field of view or optical resolution by itself.

When Does a 1 Inch Machine Vision Lens Become the Better Choice?

A 1 inch machine vision lens becomes important when the industrial camera uses a larger sensor that needs greater image circle coverage than a 2/3 inch optical design is intended to provide.

Larger sensors can be valuable for several reasons.

They may provide more pixels, larger pixels, a wider active imaging area or a combination of these characteristics. Depending on the sensor, this can support higher resolution inspection, greater light collection, a wider field of view at a given focal length or more image information across the target.

The lens must be designed to support that larger imaging area.

For example, Kyptec Automation® KL-1216 25 mm 10 MP Machine Vision Lens is specified for a 1 inch image format with a 25 mm focal length and C mount. Kyptec Automation® KL-1218 35 mm 10 MP Machine Vision Lens provides a 35 mm option within the same 1 inch format class.

These two products demonstrate why sensor format and focal length should be treated separately. Both are intended for 1 inch imaging, yet the 35 mm lens produces a narrower field of view than the 25 mm lens when used with the same sensor and working distance.

When Should You Consider a 1.1 Inch Machine Vision Lens?

A 1.1 inch machine vision lens is relevant when the camera uses a larger sensor requiring an image circle beyond conventional 2/3 inch or 1 inch coverage.

This format is particularly important in high resolution industrial imaging, where manufacturers often combine larger sensors with high pixel counts.

The larger sensor area can allow a system to capture more of the scene while still maintaining substantial pixel resolution. This can be useful in surface inspection, electronics, precision measurement, wide area inspection and systems where one camera must capture many small features in a single exposure.

The optical challenge is that image quality must remain useful across that larger sensor area.

Kyptec Automation® offers high resolution lenses in this larger format class. For example, Kyptec Automation® KL-1238 16 mm 25 MP Machine Vision Lens combines a 16 mm focal length with a 25 MP resolution class and a larger sensor format. Kyptec Automation® KL-1240 25 mm 25 MP Machine Vision Lens provides a 25 mm alternative, while Kyptec Automation® KL-1244 50 mm 25 MP Machine Vision Lens provides a longer focal length for applications requiring a tighter field of view.

For buyers, the important point is not that 1.1 inch is automatically superior to 1 inch or 2/3 inch. It is appropriate when the camera sensor actually needs that image coverage.

2/3 Inch vs 1 Inch Lens: What Changes on the Same Focal Length?

Suppose two industrial cameras use different sensor sizes but both are fitted with compatible 25 mm lenses.

One camera uses a smaller 2/3 inch sensor. The other uses a larger 1 inch sensor.

At the same working distance, the larger sensor generally captures a wider field of view because a larger portion of the lens image is being recorded.

This is an important practical difference.

Engineers sometimes replace a camera while keeping the same nominal lens focal length and then wonder why the field of view changed. The focal length did not change, but the active sensor dimensions did.

Therefore, when upgrading from a 2/3 inch camera to a 1 inch camera, do not assume that the existing inspection geometry will remain unchanged even if a compatible lens of the same focal length is fitted.

Field of view should be recalculated using the new sensor dimensions.

1 Inch vs 1.1 Inch Lens: Is the Difference Important?

Yes, particularly when the sensor approaches the limits of the smaller lens image circle.

The numerical difference between 1 inch and 1.1 inch may look modest, but larger sensor coverage places additional demands on the optical design, especially near the corners.

A lens that performs very well over a 1 inch sensor does not automatically guarantee equivalent coverage and edge performance on a larger 1.1 inch class sensor.

This is why buyers should not select a 1 inch lens for a 1.1 inch camera simply because the mount fits and the focal length is correct.

The sensor diagonal must remain inside the usable image circle.

For high resolution cameras, corner performance can become particularly important because valuable inspection pixels may extend across almost the complete sensor area.

Why a C Mount Does Not Guarantee Sensor Compatibility

C mount describes the mechanical interface between the camera and lens.

Sensor format describes the optical coverage requirement.

These are completely different specifications.

Two lenses can both use C mount while one is designed for a 2/3 inch image format and another for a 1.1 inch image format.

Both may screw onto the same C mount camera body, but that does not mean both will cover the camera's sensor correctly.

This distinction is essential for machine vision buyers.

When checking industrial camera lens compatibility, confirm at least the mount type, supported image format, focal length and required optical resolution. Mount compatibility alone is not enough.

Kyptec Automation® uses C mount across many products in its Machine Vision Lens range, while offering different image formats so the mechanical interface and sensor coverage can be matched independently.

What Happens If the Lens Format Is Too Small for the Sensor?

The most obvious problem is vignetting.

Vignetting appears as darkening toward the image corners because the lens does not adequately illuminate the complete sensor area.

In severe cases, the usable image can look almost circular because the sensor extends well beyond the lens image circle.

But dark corners are not the only concern.

A lens may technically illuminate the entire sensor while still providing weaker sharpness, contrast or correction near the edges than the inspection requires.

This matters in machine vision because a defect near the corner needs to be detected as reliably as the same defect near the centre when the entire image is part of the inspection area.

A lens that is marginal for the sensor format can therefore create inconsistent inspection performance even before obvious black corners appear.

Does Using a Larger Format Lens on a Smaller Sensor Improve Image Quality?

Sometimes the smaller sensor benefits from using the central portion of a larger lens image circle.

The central region of many lenses can show stronger image performance than the extreme edges.

However, it would be incorrect to conclude that a larger format lens is automatically sharper or better for every smaller sensor.

Optical resolution, focal length, aperture, distortion and lens design still determine performance.

A larger format lens can also have different physical dimensions or cost.

The better buying rule is simple: use a lens that comfortably covers the sensor and satisfies the required resolution. Extra image circle can be useful, but it should be a consequence of good system design rather than the sole reason for selecting the lens.

Worked Example: Camera Upgrade from 2/3 Inch to 1 Inch

Consider a machine that currently uses a 2/3 inch industrial camera with a 25 mm lens.

The inspection is stable and the complete part fits correctly within the image.

Later, the machine is upgraded to a higher specification camera using a 1 inch sensor.

The existing 25 mm 2/3 inch lens may still attach mechanically if both systems use C mount, but there are now two separate issues.

First, the lens may not provide sufficient image circle coverage for the larger sensor.

Second, even after switching to a proper 1 inch 25 mm lens, the field of view will be wider because the larger sensor records more of the optical image.

If the machine needs to maintain the previous framing, the engineer may need to increase focal length or change working distance.

This is why a camera upgrade should trigger a complete lens compatibility review rather than a simple camera replacement.

A suitable 1 inch option such as Kyptec Automation® KL-1216 can then be evaluated according to the new sensor, resolution and required field of view.

Worked Example: Why a 1.1 Inch Sensor Can Reduce Camera Count

Imagine a production system that needs to inspect a wide object containing many small features.

Using a smaller sensor, the system may need to choose between capturing the complete object and retaining enough pixels across each feature.

One approach is to use multiple cameras.

Another possible approach is a larger high resolution sensor that captures a wider physical area while still providing adequate pixel density.

If a 1.1 inch high resolution camera can meet the sampling requirement, the optical system must support the larger sensor.

This is where a compatible high resolution 1.1 inch machine vision lens becomes useful.

For example, a system requiring approximately 25 mm focal length could evaluate Kyptec Automation® KL-1240, while an application requiring greater camera distance and narrower framing could consider Kyptec Automation® KL-1244 at 50 mm.

The larger format lens does not itself reduce camera count. It enables the larger sensor to be used properly. The final system benefit comes from the combination of sensor size, camera resolution, field of view and optical coverage.

Sensor Format and Resolution Must Be Matched Together

Sensor size does not tell you how many pixels the camera contains.

A relatively large sensor can have moderate resolution and large pixels. Another sensor of similar dimensions can contain many more, smaller pixels.

This means a lens can have sufficient image circle coverage but still fail to provide the required optical resolution.

For example, moving to a larger sensor purely for more field of view is different from moving to a larger sensor with 20 MP or 25 MP class resolution for fine inspection.

The second system places significantly greater demands on the lens.

This is why the Kyptec Automation® product range separates both image format and megapixel class. A 2/3 inch 5 MP lens serves a different optical requirement from a 1.1 inch 25 MP lens even if both happen to have the same focal length.

Sensor Format and Focal Length Should Never Be Confused

Sensor format answers the question: will the lens cover the sensor?

Focal length answers a different question: how wide or narrow will the view be for a given sensor and working distance?

A 25 mm 2/3 inch lens and a 25 mm 1 inch lens may share the same nominal focal length, but they are designed for different image circle requirements.

Likewise, a 16 mm 1.1 inch lens and a 50 mm 1.1 inch lens both cover the same broad sensor class while providing very different fields of view.

This distinction helps buyers avoid one of the most common machine vision purchasing errors: selecting the correct focal length but the wrong sensor format.

Why Sensor Diagonal Is Important When Checking Lens Coverage

A rectangular sensor has width, height and diagonal dimensions.

The diagonal is especially useful for image circle compatibility because the sensor corners are the farthest points from the optical centre.

If the lens image circle is smaller than the sensor diagonal, full corner coverage is unlikely.

This does not mean that simply knowing the diagonal solves every compatibility question. The lens manufacturer may specify supported optical format rather than an exact image circle diameter, and actual usable edge quality may vary.

Still, understanding sensor diagonal helps explain why a lens can cover the width and height near their centres but still show corner problems.

The corners impose the greatest image circle requirement.

Why Aspect Ratio Can Affect Sensor Matching

Not every industrial sensor has exactly the same aspect ratio.

Two sensors can have similar diagonals while distributing that image area differently between width and height.

This can affect how the lens image circle is used.

For most industrial purchasing decisions, selecting a lens specified for the camera's sensor format is the practical starting point. For unusual sensor geometries or demanding edge performance, checking the actual width, height and diagonal is safer than relying on the format label alone.

This becomes especially important when the machine uses virtually the entire sensor area for measurement or defect detection.

Should You Oversize the Lens Format for Future Camera Upgrades?

Sometimes it is sensible.

An OEM designing a machine platform may expect a future upgrade from a 2/3 inch camera to a 1 inch camera. Selecting a suitable 1 inch lens from the beginning can potentially simplify that upgrade, provided the lens also meets the present camera's focal length and resolution requirements.

However, future proofing should be planned rather than assumed.

A future camera may use not only a larger sensor but also much smaller pixels and a significantly higher resolution. The existing lens may cover the new sensor but still lack the required optical resolution.

The future camera may also require a different focal length because its larger sensor changes the field of view.

Therefore, image format headroom is useful, but it is only one part of upgrade compatibility.

How to Match a Machine Vision Lens to Your Camera Sensor Before Buying

Start with the industrial camera datasheet.

Identify the active sensor model if available, sensor width, sensor height, diagonal, pixel size and total resolution.

Next identify the camera lens mount.

Then determine the minimum lens image format required to cover the sensor.

After that, calculate the focal length needed from field of view and working distance.

Finally, choose an optical resolution class suitable for the camera pixel density and inspection task.

This sequence is much safer than beginning with a product search for “25 mm C mount lens” and trying to make it fit afterward.

The Kyptec Automation® Machine Vision Lens collection is structured across different focal lengths, resolutions and image formats, allowing these specifications to be considered together.

Frequently Asked Questions About 2/3 Inch, 1 Inch and 1.1 Inch Machine Vision Lenses

1. Can I use a 1 inch machine vision lens on a 2/3 inch camera?

Generally, a lens designed to cover a 1 inch image format can provide sufficient image circle for a smaller compatible 2/3 inch sensor, assuming the mount, focal length, resolution and other specifications are suitable. The smaller sensor normally uses a more central portion of the lens image. However, buying a larger format lens is not automatically necessary if an appropriate 2/3 inch lens already satisfies the application.

2. Can I use a 2/3 inch lens on a 1 inch industrial camera if there are no black corners?

The absence of obvious black corners does not necessarily prove that the combination is ideal. Illumination, sharpness, distortion or contrast may still deteriorate toward the edges. For an inspection that uses the complete sensor, a lens designed for the required image format is the safer choice. Kyptec Automation® provides dedicated 1 inch options such as Kyptec Automation® KL-1216 and Kyptec Automation® KL-1218 for compatible cameras.

3. Why does my camera show dark corners after changing to a larger sensor?

The most likely optical explanation is that the lens image circle is too small for the new sensor. The larger sensor reaches farther toward the outer area of the projected image, where coverage may be insufficient. Check the lens image format against the new camera sensor dimensions before changing exposure or software settings to compensate.

4. Does changing from a 2/3 inch to a 1 inch sensor change field of view?

Yes. With the same focal length and working distance, the larger sensor generally records a wider field of view. Therefore, changing camera sensor format can alter framing even when focal length stays unchanged. The field of view should be recalculated whenever the sensor dimensions change.

5. Is a 1.1 inch lens physically larger than a 2/3 inch lens?

It can be, because creating a larger image circle often requires a different optical design, but physical size cannot be determined from image format alone. Lens dimensions depend on focal length, aperture, optical construction and housing. Always check the mechanical drawing when installation space is limited.

6. How do I find the real sensor size of my industrial camera?

Check the camera datasheet or the datasheet for the image sensor used inside the camera. Look for active sensor width, active sensor height, diagonal and pixel pitch. Do not calculate the dimensions by converting the nominal 2/3 inch, 1 inch or 1.1 inch label directly into millimetres.

7. Is sensor format the same as lens mount size?

No. Sensor format refers to optical coverage, while the lens mount defines the mechanical interface. A 2/3 inch lens and a 1.1 inch lens can both use C mount. Always check both specifications separately when purchasing an industrial camera lens.

8. What happens if the lens image circle is much larger than my sensor?

The camera simply records a central portion of the available image circle. This can be perfectly acceptable if focal length, resolution, mount and optical performance match the application. The main considerations are whether the larger format lens offers useful benefits and whether its cost or physical dimensions fit the system.

9. Can software remove vignetting caused by a lens that is too small for the sensor?

Software can sometimes compensate for moderate brightness shading, but it cannot recover optical information that the lens never delivered properly. Severe image circle mismatch, poor corner resolution or missing coverage cannot be solved reliably through software correction. Selecting a lens with adequate sensor coverage is the correct starting point.

10. Which sensor format is better for a wide field industrial inspection?

A larger sensor can provide a wider field of view at a given focal length, but “better” depends on the complete application. A larger sensor may be useful when a wide scene and high pixel count are both required. A smaller sensor can be perfectly adequate for compact inspections. The lens must match whichever sensor format provides the required resolution and field coverage.

11. Do I need a 1.1 inch lens for every 25 MP industrial camera?

Not necessarily. Camera megapixel count does not determine sensor dimensions by itself. A 25 MP camera can use different sensor sizes depending on pixel pitch and design. Check the actual sensor format first. Kyptec Automation® offers 25 MP lenses in a larger format class for compatible sensors, including Kyptec Automation® KL-1238, Kyptec Automation® KL-1240 and Kyptec Automation® KL-1244.

12. Why are the image corners less sharp than the centre on a large sensor?

Lens performance generally becomes more challenging toward the edge of the image circle. If the sensor is close to the lens's coverage limit, corner aberrations or reduced contrast can become more visible. A properly matched lens designed for the sensor format and resolution requirement helps reduce the risk of edge performance becoming the inspection bottleneck.

13. Should I match the lens to the sensor diagonal or sensor width?

For image circle coverage, sensor diagonal is especially important because the corners lie farthest from the optical centre. For field of view calculations, use the relevant active sensor width or height. These are two different calculations, so both types of dimensions matter during machine vision lens selection.

14. Can a camera with the same megapixel count need a different lens after a sensor change?

Yes. Two cameras can have the same pixel count but different physical sensor sizes and pixel pitches. The new camera may require a larger image circle, may produce a different field of view with the same focal length and may place different resolution demands on the optics. Lens compatibility should be reviewed even when the megapixel count remains unchanged.

15. What camera information should I send to a lens supplier to confirm sensor compatibility?

Send the camera model, sensor model if known, active sensor width and height, nominal image format, resolution, pixel size, mount type, required field of view and working distance. This allows a suitable focal length, image format and resolution class to be selected together. When evaluating the Kyptec Automation® Machine Vision Lens range, these details make it easier to narrow the available options to lenses that are genuinely relevant to the camera.

Which Format Should You Finally Choose?

Choose a 2/3 inch machine vision lens when the industrial camera uses a compatible 2/3 inch class sensor and the lens resolution, focal length and mount meet the inspection requirement.

Move toward a 1 inch machine vision lens when the camera sensor requires a larger image circle or when a machine upgrade uses a larger sensor that should be fully covered without relying on marginal edge performance.

Choose a 1.1 inch machine vision lens when the camera uses a larger format sensor requiring still greater image circle coverage, particularly in high resolution industrial imaging where the complete sensor area contains useful inspection information.

Do not choose the format simply because a larger number sounds better.

The objective is to make the lens image circle comfortably cover the camera sensor while providing the required image quality across the region that the vision algorithm actually uses.

A 2/3 inch camera may be correctly paired with a 2/3 inch lens such as Kyptec Automation® KL-1208 for a compatible 25 mm, 5 MP application. A 1 inch camera may require a product such as Kyptec Automation® KL-1216 at 25 mm or Kyptec Automation® KL-1218 at 35 mm when those focal lengths fit the geometry. A compatible larger high resolution sensor may instead call for a 1.1 inch class lens such as Kyptec Automation® KL-1238, Kyptec Automation® KL-1240 or Kyptec Automation® KL-1244.

The benefit of the Kyptec Automation® lens range is that sensor format does not have to be considered in isolation. Engineers and OEMs can compare machine vision lenses by image format, focal length and resolution so the optical system can be matched to the camera rather than simply attached to it.

The final check before buying should therefore answer five questions.

Does the lens mount fit the camera?

Does the lens image format comfortably cover the complete active sensor?

Does the focal length provide the required field of view at the available working distance?

Does the optical resolution match the camera pixel density and smallest inspection feature?

Will image quality remain adequate across the part of the sensor actually used by the inspection?

When all five answers are satisfactory, the difference between 2/3 inch, 1 inch and 1.1 inch stops being confusing. It becomes a straightforward sensor coverage decision.

That is the practical way to match a machine vision lens with an industrial camera sensor format.