First of all, it is necessary to determine the interface, target size and resolution size of the industrial camera. For example, it is a 2/3" industrial camera, C-mount, 5 megapixels; then we can first determine that the required industrial lens is C-mount, at least support 2/3", 5 megapixels or more, or the line pair is 160LP.
Secondly, determine the field of view (FOV) and working distance (WD) to be achieved, and then calculate the focal length (f) of the industrial lens according to these two requirements and the known target surface size. Its calculation formula is:
Focal length f = WD × target size (H or V) / FOV (H or V)
Field of view FOV (H or V) = WD × target size (H or V) / focal length f
FOV (H or V) = target size (H or V) / optical magnification
Working distance WD = f (focal length) × target surface size/FOV (H or V)
Optical magnification = target size (H or V) / FOV (H or V)
For example, the field of view is 100*100mm, and the WD. is 500mm; then we first determine the focal length from the working distance to be less than 50mm, and the focal lengths of industrial lenses on the market are generally 12mm, 16mm, 20mm, 25mm, 35mm, 50mm, 75mm. Combined with the size of the camera target surface to determine which model, the smaller the focal length of the industrial lens, the larger the field of view, and the larger the field of view.
If the target surface is 2/3", you can choose an industrial lens with a 35mm focal length; if the target surface is 1/2", you need an industrial lens with a 25mm focal length, or smaller.... and so on.
In the process of industrial lens selection, in order to facilitate the calculation of industrial lens parameters, the target surface size table is now provided for reference.
1.1 inches - the target surface size is 12mm wide * 12mm high, 17mm diagonal
1 inch - the target surface size is 12.7mm wide * 9.6mm high, 16mm diagonal
2/3 inch - the target surface size is 8.8mm wide * 6.6mm high, 11mm diagonal
1/1.8 inch - the target surface size is 7.2mm wide * 5.4mm high, 9mm diagonal
1/2 inch - the target surface size is 6.4mm wide * 4.8mm high, 8mm diagonal
1/3 inch - the target surface size is 4.8mm wide * 3.6mm high, diagonal 6mm
1/4 inch - the target surface size is 3.2mm wide * 2.4mm high, 4mm diagonal