Colour − magnitude diagrams that are used to define the lens sample selection. In grey we show the locations of the galaxies with m_r′ < 21.5 from the W1 photometric redshift catalogue from the CFHTLenS collaboration (Hildebrandt et al. 2012). In the top row we show the late-type galaxies with an absolute magnitude M_r′ <  −22.5, in the second row we show the late-types with M_r′ > −22.5, and in the third and fourth row we show the early-types with M_r′ < −22.5 and M_r′ > −22.5, respectively. The coloured boxes illustrate the lens sample selection criteria; all galaxies that reside in all the red dashed (green solid) boxes form the “red” (“blue”) lens sample. We find that the “red” lens sample contains very few late-types, as they are excluded in the g′ − r′ versus g′ diagram (first column). Also, most faint early-type galaxies are excluded from this sample as well (see, e.g., the third and fourth columns). For the “blue” lens sample, we cannot define selection criteria that exclusively select bright late-type galaxies, and this sample therefore also contains a number of faint late-type and early-type galaxies.