1x-Flat Field for sharper stars all to way to the edge. Specifically made for the 60mm APO. Screws on to the M63x1-Thread. The spotdiagrams show that all colors are well corrected up to APS-C. ♦ 1x factor ♦ 55 mm to 60 mm back distance - fine tune in 0,05 mm Increments - from the M48x0,75-thread
