Balluff MATRIX VISION mvBlueGEMINI Technical Manual page 39

The resolution - a little physics
Actually, you have to consider the wavelength of the light, because the light makes the image.
The wavelength of the visible light is between 0.4 µm and 0.6 µm.
The smallest imaged point results from the aperture which will never be smaller than 0.5
µm. Realistic figures are between 2 µm and 5 µm.
B = 1.22 * 2 * λ * F / D
B = Diffraction disk or point image
F = Focal length
D = Aperture diameter
Example with green light and λ = 0.5 µm
F-number F/D
1
4
16
mvBlueGEMINI Technical Manual (EN)
Diameter diffraction disk
1.25 µm
5 µm
20 µm
v2.6
38
APPENDIX