Comparing Canon’s MKII and MKIII Extenders

In the Fall of 2010 Canon announced the introduction of new MKIII extenders to replace the previous MKII versions.  Super Spectra coatings were introduced to help reduce ghosting and flare as well as fluorine coating to make water spots and finer prints easier to remove.  I’ve always fond the MKII extenders to be extremely useful when used in the right circumstances so I was eager to try out the MKIII versions to see if there was an improvement. Physical differences Since the introduction of the 800mm f5.6, Canon changed their off-white color of their telephoto lenses.  All the new MKII