Lens calculator - Calculating the working distance gThe object distance refers to the distance between the object (test object) and the centre of the optic lens groups. This refers to the working distance by approximation: The object distance is the distance to the centre of the lens group.
g= f´* (G /B +1)
Note: Even when using the drop-down lists own values can be entered. Please use the first entry "user def."!
Attention: Calculated working distances below 150 to 300 millimetres cannot be focused using normal C-mount lenses. In case of F-mount lenses and other lenses for larger image circle diameters, the minimum lens distances are often considerably larger. By means of additional spacers, however, the lens distance can be reduced ("see calculation of close-up rings"). The calculated working distances refer to the optic centre of the lens housing. Especially in case of very small working distances of several centimetres, the calculated values are no longer realistic. In case of smallest image details and large magnifications please use macro-lenses which are specially designed for these applications. Further details on optical calculations can be found in chapter Optical basics.