The Multi-Purpose Coma Corrector (MPCC) Mark III eliminates coma across the full photographic field without manipulating the focal length. The proprietory lens design has the Phantom Group wideband multicoating on all air to glass surfaces. This treatment delivers the highest transmission combined with the lowest amount of scatter and reflections across a very wide spectral range from UV to NIR. The original MPCC had been designed for an f/ratio of f/4.5 to f/6 but this version works even down to f/3.5. Stars remain pinpoints across the field and the visual use likewise is made much easier - with the help of the 2" (M48) male filter thread at the eyepiece facing side.
The base-element 2858400A is prepared for use with a DSLR and a standard T-ring, it can be used over the T-2 thread on all standard T-rings. Since the T-thread vignettes with cameras with larger sensors (such as full-format DSLRs), the T-2 thread can be removed. Then an M48 thread is free, and the free aperture increases from 38 to 44 mm. The M48 spacer ring for MPCC III / Protective EOS T-ring can be connected directly to the Protective CANON DSLR T-ring.