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Online lens calculator - Calculating measurement errors caused by height variations

The use of an ordinary entocentric lens can easily cause measuring errors. As opposed to a telecentric lens, the field of view is dependent on the working distance. This is caused by the fixed opening angle of an entocentric lens.

Height deviation of test objects can therefore lead to measurement errors. Caution: The calculated error refers to the image corners! This error will be "0" in the middle of the image and will have its maximum in the image corners.

Calculation of measurement error with different working distance

Note:Even when using the drop-down lists own values can be entered. Please use the first entry "user def."!


Sensor size:
Sensor size in pixels:
Focal length of lens:
Working distance in mm:
Variation of distance or variation
of object height (+ / - mm):


Calculated opening angle of lens:
Calculated field of view:
Length variation for total field of view in mm:
Max. length variation for object at one side
of image corner caused by height variance :
(center of image=0...image corner=max)


Attention: For accurate measurements, it is essential to use telecentric lenses! Also geometric distortion is also substantially lower.

For further details on optical calculations, see chapter "Entocentric lenses" or chapter "Telecentric lenses".

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