Can someone please confirm that the distance to sensor from the front threads to the face is 44mm on a 5D mark II?
I am having difficulty verifying this.
I just bought an aplanatic coma corrector and the distance is crucial (spacing).
Canon online documentation suggests it s 44mm from the sensor surface to flange face but focal distance can vary based on lense or coma corrector required spacing. For example the Baader MPCC last optical surface will be further away from the sensor then the corrector flange, I believe the MPCC requires 50mm so the gap is 6mm. Canon doco suggests all EOS cameras have the same sensor setback.
if getting from the TS i'd email them and they will help you with the spacer solution.
GPU Aplanatic Newtonian Coma Corrector 4-element ... Newtonian Super Coma Corrector for Newtonian telescopes from f/4 ... designed by Pal Gyulai - Hungary
Optimised for superfast f/4 imaging Newtonian telescopes from TS Optics (UNC / ONTC) Skywatcher Quattro, GSO and many more , delivering stunning wide-field views with pinpoint stars to the edge of the flat field. This corrector is made in Hungary (GPU Optics) and it is the best corrector for fast newtonian telescopes without changing the focal lengh, we know. The corrector is also sold by Skywatcher.
Specifications:
-- Magnification remains unaltered. -- Features a 4 x element design with one element made from FPL51 ED glass. -- Requires 55mm back focus. -- Length of the Corrector ... 100mm -- Outside diameter 50.8mm. -- A suitable M48x0.75 adaptor is required to match your camera.
The optimal back focus depends on the telescope's focal length: F=600mm, working distance = 51.66mm F=800mm, working distance = 53.66mm F=1000mm, working distance = 55.0mm F=1200mm, working distance = 54.66mm > 1500mm, working distance = 54.60mm
