The depth of field (focal tolerance), in turn, specifies the area in that the laser beam is optimally focused. The longer the focal distance, the longer the depth of field. This means that the depth of field of a 5 inch lens will be about twice as long as for a 2.5 inch lens. For this reason, the cutting edge of thicker materials will turn out straighter when a 5 inch lens is used than when a 2.5 inch lens is used.
At the same time, the laser beam diameter will be greater the longer the focal distance is (for a 5.0 inch lens approx. twice as big as for a 2.5 inch lens). As a result, the energy of the laser (wattage) will be distributed onto a larger surface. Consequently, less power (here in the form of heat) per surface area will be applied. The use of a lens with a greater focal distance can therefore be advantageous for materials that react sensitively to heat (e. g. laminates). The greater focal diameter means a greater line width. Filling lines can therefore be cut with the laser at a greater distance and thus faster.
The following table gives you a general overview of the various areas of use. However, you should adapt this information to your specific application.