This ILensType interface provides the minimal set of information that a lens object shall provide in a vision system. All objects that implement this interface shall be organized in the Lenses folder of the VisionSystemAssetType. It is formally defined in Table 33.

Figure 20 – ILensType

Table 33 – ILensType Definition

Attribute	Value
BrowseName	ILensType
IsAbstract	True
References	Node Class	BrowseName	DataType	TypeDefinition	Other
Subtype of the IVisionInfoType, inheriting the InstanceDeclarations of that Node.

The components of the ILensType have additional subcomponents which are defined in Table 34.

Table 34 – ILensType Additional Subcomponents

Source Path	Reference	NodeClass	BrowseName	DataType	TypeDefinition	Others
2:Maintenance	0:HasComponent	Variable	MountType	0:UInt32	0:MultiStateDiscreteType	O
2:Maintenance	0:HasProperty	Variable	LensType	0:String	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	FocalLength	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	Aperture	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	ModulationTransferFunction	0:Byte	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	Resolution	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	BackFocalLength	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	MinimumWorkingDistance	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	Magnification	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	WorkingDistance	0:Double	0:PropertyType	O
2:Maintenance	0:HasProperty	Variable	OpticalFormat	0:String	0:PropertyType	O

The FocalLength property is the distance between the principal plane and the point where the light passing through the lens is focused and is given in millimeters.

The BackFocalLength property is the distance from the vertex of the last optical surface of the system to the rear focal point and is given in millimeters. This property should only exist when needed to provide additional system information such as to calculate the scheimpflug angle for tilted systems.

The Aperture property is the current aperture set on the lens. Examples are “1.4” and “2.0”.

The Resolution property is the resolution that the lens is capable of (this is usually the catalog value). It is given in line pairs per millimeter (lp/mm) as the resolution would be determined with something like a 1951-USAF resolution target.

The MinimumWorkingDistance property is the minimum object distance where you can still get a sharp image and is given in meters.

The ModulationTransferFunction property is the ratio expressed as a percentage, between the actual contrast in the scene and the contrast transferred by the lens to the image at a given resolution.

The Magnification property is the relation between object size and image size. An example value of 1 will deliver a life-sized image. This property usually needs to be provided for Telecentric lenses only but might also be calculated for other lens types.

The WorkingDistance property is the current distance from the object to the lens and is given in meters.

The LensType property is the type of the Lens. Examples are “Macro”, “Telecentric” and “Tilt-Shift”.

The MountType component is an enumeration using MultiStateDiscreteType that defines the mount type of the Lens. In Table 35 standardized values for the EnumStrings are defined.

The OpticalFormat property denotes the maximum size of the sensor that the lens is suitable for (typically in inches).

Table 35 – ILensType Attribute values for child Nodes

BrowsePath	Value Attributes
2:Maintenance MountType 0:EnumStrings	CUSTOM CS-MOUNT D-MOUNT A-MOUNT F-MOUNT T-MOUNT E-MOUNT EF-MOUNT V-MOUNT

Note: Servers can add additional entries into the EnumStrings array. The order of the value attributes corresponds with the numeric value that must be provided in the value of the variable.