In this work we describe some of the defects in SiC observable using different optical characterisation techniques. This includes photoluminescence measurements to determine the presence of different defects. We also show that optical techniques can be developed for mapping characterisation, which are useful both for routine measurements and for determine spatial variations and presence of defects over larger areas. One such example is the lifetime mappings on epitaxial layers on entire wafers, which has shown the importance of structural defects replicated into the epitaxial layer. Optical measurements have also been correlated to structural measurements from X-ray topography to demonstrate the importance of the structural defects