Lens calculator  Calculating the focal length
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 Cmount lenses are e.g. (1.8, 2.8, 4, 6,) 8, 12, 16, 25, 35, 50 and 75 mm.
Calculating the focal length using sensor size, working distance and object size
Note: Even when using the dropdown lists own values can be entered. Please use the first entry "user def."!
Sensor size :  
Length of inspected part in mm (field of view FOV):  
Working distance in millimeters:  
Calculated focal length of lens:  

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Attention: Calculated focal lengths below 1.4 mm or beyond 500 mm are declared unrealistic. Extreme values are nevertheless displayed. Please observe that very small working distances below the closeup limit can only be realised using additional closeup rings. In the extremely close range (few cm), the focal lengths cannot be calculated precisely due to simplified approximate computation and unknown dimensions of the lenses. Please use macrolenses for this purpose!
Focal length: Calculate with information of pixel sizes
Note: Even when using the dropdown lists own values can be entered. Please use the first entry "user def."!
Sensor pixel count in X direction:  
Sensor pixel count in Y direction:  
Pixel size in µm:  
Working distance in mm:  
Object length in mm:  
Object width in mm:  
Object diagonal in mm:  
Calculated sensor dimensions:  
Calculated sensor ratio:  
Focal length:  

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Further details on optical calculations, such as the focal length calculation, can be found in chapter Optical basics.