MTF and wavefront error can be measured at multiple wavelengths using Phasics wavefront sensors. These sensors are polychromatic and have higher lateral resolution (up to 400 x 300) compared to standard Shack-Hartmann sensors. They are also insensitive to vibration. So you get interferometer like performance at many wavelengths in most environments. A range of MTF solutions can be made to meet most customer’s needs.