- Cross-polarization is a two-step filtering process using two linear polarizer filters—one on the flash oriented either horizontally or vertically, and one on the lens oriented 90 degrees off the axis of the flash filter. - This causes the light illuminating the teeth to be filtered for one direction of light wave; then the reflected light is organized in the contrasting direction as it passes through the filter/lens combo and is recorded by the DSLR sensor. **For further product information , please contact Chat Support**