Using marks of known dimensions and size, and spacing, a 
zoom lens may be calibrated in either or both the X and Y spatial directions. A 
system comprising an 
image capture device, positioning means, position 
encoder means, 
operator interface, and 
processing unit permits this method to be advantageously applied to a wide variety of web inspection / control functions, including but not limited to initial web registration, multiple color ink registration, lateral web positioning, repeat length calculations, 
image capture synchronization, thermal / mechanical differential compensation, and accurate registration of objects within an image to other objects within an image or to a mechanical reference on a 
machine. Since the 
Zoom Calibration method permits a 
system to be constructed with both wide / variable 
field of view and accurate 
distance measurement positioning and calibration, all of the web inspection / control functions traditionally used in the web printing industry may be implemented with a single inspection / 
control system using a multitasking approach with the same inspection / control hardware. This permits rapid implementation of old and new web inspection / control functions at a greatly reduced cost as compared to traditional fixed lens systems, as well as permitting a degree of 
automation, remote access, diagnostic control, 
quality assurance, and product 
quality control heretofore not possible with conventional web inspection / control systems.