The focal length (f´) virtually serves to calculate the required lens and is thus the most important specification to characterise an (entocentric) normal lens.
The theoretic value of the focal length calculation serves to find the best suitable optics. Typical increments of focal lengths for C-mount lenses are e.g. 1.8, 2.8, 4, 6, 8, 12, 16, 25, 35, 50 and 75 mm.

The focal length (f´) virtually serves to calculate the required lens and is thus the most important specification to characterise an (entocentric) normal lens.
The theoretic value of the focal length calculation serves to find the best suitable optics. Typical increments of focal lengths for C-mount lenses are e.g. 1.8, 2.8, 4, 6, 8, 12, 16, 25, 35, 50 and 75 mm.

The object size (y) is usually the object range to be detected which must be viewed by means of the camera.

Calculate the field of view given the working distance, sensor size and lens focal length.

The object size (y) is usually the object range to be detected which must be viewed by means of the camera.

Calculate the object size parameters (height, width, diagonal) using real sensor dimensions here.

The object size (y) is usually the object range to be detected which must be viewed by means of the camera.

For macro lenses and telecentric lenses it is possible to calculate the field of view using the imaging scale and sensor size here.

The object size (y) is usually the object range to be detected which must be viewed by means of the camera.

The field of view at a given working distance can also be calculated using the aperture angle of the optics here.

The object distance refers to the distance between the object ("test object", "scene", also "field of view") and the first principal plane of the lens groups somewhere in the optical system. The often wanted, so-called "free working distance", from the test object to the front surface of the lens can only be calculated by specifying the position and distance of the two principal planes and the real lens length.
This means that the "working distances" calculated here are only approximate values.

The object distance refers to the distance between the object ("test object", "scene", also "field of view") and the first principal plane of the lens groups somewhere in the optical system. The often wanted, so-called "free working distance", from the test object to the front surface of the lens can only be calculated by specifying the position and distance of the two principal planes and the real lens length.
This means that the "working distances" calculated here are only approximate values.

The object distance refers to the distance between the object ("test object", "scene", also "field of view") and the first principal plane of the lens groups somewhere in the optical system. The often wanted, so-called "free working distance", from the test object to the front surface of the lens can only be calculated by specifying the position and distance of the two principal planes and the real lens length.
This means that the "working distances" calculated here are only approximate values.

Entocentric lenses have a fixed aperture (opening) angle. Therefore the object field to be viewed can be increased or reduced by increasing or reducing the working distance. If the aperture angle is very large, a strong distortion of the optics must usually be expected.

Entocentric lenses have a fixed aperture (opening) angle. Therefore the object field to be viewed can be increased or reduced by increasing or reducing the working distance. If the aperture angle is very large, a strong distortion of the optics must usually be expected.

The depth of field (DOF) is the range within which the object can move away from or towards the camera without resulting in a blurred image. The depth of field depends on the adjusted lens aperture, the distance to the test object, the focal length and the pixel size of the camera. the double pixel size is often set taken permissible unsharpness, i.e. one pixel image unsharpness is accepted.
In an existing system, the field of depth can only be varied by means of the aperture of the lens.

Usually no focal length is indicated for telecentric measuring lenses or macro-lenses, which would serve to calculate and select the optics. These lens types are characterised by the imaging scale β (beta). It can easily be calculated.
Using sensor size and object size

Usually no focal length is indicated for telecentric measuring lenses or macro-lenses, which would serve to calculate and select the optics. These lens types are characterised by the imaging scale β (beta). It can easily be calculated.
Using focal length and object size

The values of the focal ratio indicated on the lens are normally calculated for an image from the infinite. In case of images from a short distance, particularly macro-images, the effective focal ratio can be calculated which results in the actual image brightness: