Contact-free optical extension measuring methods become more and more important in material testing. They are primarily adopted when mechanically sensitive materials or temperature conditioning devices are used during the measurement. The so-called laser speckle method (laser speckle extensometer) achieves very good results in that field. It has been especcially redeveloped by Hegewald & Peschke GmbH for contactless extension and deformation measurement. The operating principle of this method is based on the analysis of speckle patterns which result from the reflection of a coherent laser beam off the surface of the specimens. One or several professional cameras record the pattern and analyse it reliably with the help of analysis of correlation. The unique pattern is used as imaginery gauge mark. During the test the distances within the pattern are measured and thus the extension can be calculated.